Dissertations / Theses on the topic 'Single-phase dc/ac converter'
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Gitau, Michael N. "Optimal PWM switching strategy for single-phase AC-DC converters." Thesis, Loughborough University, 1994. https://dspace.lboro.ac.uk/2134/7205.
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The thesis describes an optimal selective harmonic elimination strategy suitable for singlephase AC-DC converter-fed traction drives. The objective is to eliminate low-order supply current harmonics, including those injected into the supply due to load-side current ripple. Other advantages that the switching strategy has to offer over phase-control include improved supply power factor, reduced VA consumption for a given demand speed and load, reduced torque and speed ripple and smaller armature circuit smoothing inductance. The effect of field current boost on the dynamic response of the drive is also described. It is shown that field boost helps to reduce the speed rise-time by increasing the electromagnetic torque available during acceleration periods. Closed-loop control of a 4-quadrant DC drive is described and a comparison made between the performance of PID-control and pseudo-derivative feedback control. It is shown that pseudo-derivative feedback control has several advantages to offer, amongst which are ease of tuning of the controller gains and a superior performance following load torque disturbances. A laboratory size drive system was designed and built, and used to validate simulation predictions for both the switching strategy and pseudo-derivative feedback control. A microcontroller based hardware implementation of both the switching strategy and a digital pseudo-derivative feedback controller was adopted, with the switching strategy being implemented using an off-line approach of precalculating the switching angles and storing these in look-up tables. The armature voltage controller comprises a dual-converter employing IGBTs as switching devices. The use of IGBTs allows higher switching frequencies at significant power levels than would be possible if GTOs were used. It also simplifies the gate drive circuit design and minimises the need to use snubber circuits.
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LI, QIANG. "A SINGLE-PHASE DUAL-OUTPUT AC-DC CONVERTER WITH HIGH QUALITY INPUT WAVEFORMS." UKnowledge, 2003. http://uknowledge.uky.edu/gradschool_theses/242.
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A single-phase, buck-boost based, dual-output AC-DC converter is studied in this thesis. The converter has two DC outputs with opposite polarities, which share the same ground with the input power line. The power stage performance, including the input filter, is studied and procedure to select power components is given. The circuit model is analyzed to develop appropriate control. Zerocrossing distortion of the source input current is addressed and a solution is proposed. Experimental results are satisfactory in that a high power factor line current results for steady-state operation.
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Santos, Heron Alves dos. "Design of a controlled single-phase ac-dc converter for interconnection of DC and AC buses of a microgrid." Universidade Federal do CearÃ, 2014. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=12977.
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The recent growth expectation of the participation of solar-photovoltaic energy sources in the power generation matrix has significantly increased the number of grid-connected systems. For connection to power grid, it is essential to use a dc-ac converter, which is able to suit the characteristics of the power provided by the photovoltaic modules to grid parameters. This dissertation presents a project proposal of a 2 kW single phase dc-ac converter for connecting a 311 V dc bus to a 220 Vrms ac bus of a microgrid. The proposed converter is bidirectional and allows, when necessary, the power flow from ac to dc bus. The study shows, through simulation and prototype implementation in the laboratory, that with the application of an appropriate control strategy it is possible to control the direction of power flow, as well as properly modulating the current flowing between two buses, dc, powered by photovoltaic panels and the battery bank, and the ac, at grid side. The prototype had a yield of about 91% and has injected electric current with low harmonic content (THDi less than 5%).A recente expectativa de crescimento da participaÃÃo da energia solar-fotovoltaica na matriz de geraÃÃo de energia elÃtrica aumentou significativamente o nÃmero de conexÃes desses sistemas à rede elÃtrica. Para que a interligaÃÃo com a rede elÃtrica convencional seja possÃvel, à indispensÃvel a utilizaÃÃo de conversores CC/CA, capazes de adequar as caracterÃsticas da energia disponibilizada pelos mÃdulos fotovoltaicos aos padrÃes da rede. Esta dissertaÃÃo apresenta uma proposta de projeto de conversor CC/CA de 2 kW para conexÃo de dois barramentos de uma microrrede, um CC em 311 V e outro CA em 220 Vrms. O conversor proposto à bidirecional e permite, quando necessÃrio, o fluxo de energia elÃtrica do barramento CA para o CC. O estudo realizado mostra, atravÃs de simulaÃÃes e de implementaÃÃo de protÃtipo em laboratÃrio, que com a aplicaÃÃo de uma estratÃgia de controle adequada à possÃvel controlar o sentido do fluxo de potÃncia do conversor, assim como modular apropriadamente a corrente que flui entre dois barramentos, o CC, alimentado por painÃis fotovoltaicos e por banco de baterias, e o barramento CA, do lado da rede elÃtrica. O protÃtipo desenvolvido apresentou rendimento de cerca de 91% e forneceu corrente elÃtrica de baixo conteÃdo harmÃnico (THDi menor que 5%).
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Wang, Kunrong. "High-Frequency Quasi-Single-Stage (QSS) Isolated AC-DC and DC-AC Power Conversion." Diss., Virginia Tech, 1998. http://hdl.handle.net/10919/29394.
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The generic concept of quasi-single-stage (QSS) power conversion topology for ac-dc rectification and dc-ac inversion is proposed. The topology is reached by direct cascading and synchronized switching of two variety of buck or two variety of boost switching networks. The family of QSS power converters feature single-stage power processing without a dc-link low-pass filter, a unidirectional pulsating dc-link voltage, soft-switching capability with minimal extra commutation circuitry, simple PWM control, and high efficiency and reliability.
A new soft-switched single-phase QSS bi-directional inverter/rectifier (charger) topology is derived based on the QSS power conversion concept. A simple active voltage clamp branch is used to clamp the otherwise high transient voltage on the current-fed ac side, and at the same time, to achieve zero-voltage-switching (ZVS) for the switches in the output side bridge. Seamless four-quadrant operation in the inverter mode, and rectifier operation with unity power factor in the charger (rectifier) mode are realized with the proposed uni-polar center-aligned PWM scheme. Single-stage power conversion, standard half-bridge connection of devices, soft-switching for all the power devices, low conduction loss, simple center-aligned PWM control, and high reliability and efficiency are among its salient features. Experimental results on a 3 kVA bi-directional inverter/rectifier prototype validate the reliable operation of the circuit. Other single-phase and three-phase QSS bi-directional inverters/rectifiers can be easily derived as topological extensions of the basic QSS bi-directional inverter/rectifier.
A new QSS isolated three-phase zero-voltage/zero-current-switching (ZVZCS) buck PWM rectifier for high-power off-line applications is also proposed. It consists of a three-phase buck bridge switching under zero current and a phase-shift-controlled full-bridge with ZVZCS, while no intermediate dc-link is involved. Input power and displacement factor control, input current shaping, tight output voltage regulation, high-frequency transformer isolation, and soft-switching for all the power devices are realized in a unified single stage. Because of ZVZCS and single-stage power conversion, it can operate at high switching frequency while maintaining reliable operation and achieving higher efficiency than standard two-stage approaches. A family of isolated ZVZCS buck rectifiers are obtained by incorporating various ZVZCS schemes for full-bridge dc-dc converters into the basic QSS isolated buck rectifier topology. Experimental and simulation results substantiate the reliable operation and high efficiency of selected topologies.
The concept of charge control (or instantaneous average current control) of three-phase buck PWM rectifiers is introduced. It controls precisely the average input phase currents to track the input phase voltages by sensing and integrating only the dc rail current, realizes six-step PWM, and features simple implementation, fast dynamic response, excellent noise immunity, and is easy to realize with analog circuitry or to integrate. One particular merit of the scheme is its capability to correct any duty-cycle distortion incurred on only one of the two active duty-cycles which often happens in the soft-switched buck rectifiers, another merit is the smooth transition of the input currents between the 60o sectors. Simulation and preliminary experimental results show that smooth operations and high quality sinusoidal input currents in the full line cycle are achieved with the control scheme.Ph. D.
5
Shams, Arasto. "Sensor based measurements of a single phase AC/DC converter to estimate lifetime." Thesis, KTH, Skolan för elektroteknik och datavetenskap (EECS), 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-282878.
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Maintenance of power electronic systems is of interest for larger systemsentirety. The reason is that they in turn could affect the whole system and cause failures if they are not functional. Maintenance of systems that are critical to be functional at all times is an area of research that is developing. For power electronics, there is more research needed in the specific area of when failures will occur and the health of the system. In the following thesis, research in the field is done to examine what causes the failures and how to prevent them at most. Further,a sensor based measurement system is developed to collect data in forms that are considered to be useful for the lifetime of the converter and the degradation. The data is further processed and analyzed with estimation methods relevant for the research.Underhåll av kraftelektronik är ett intressant område för ett större systems helhet. Orsaken är att det kraftelektroniska systemets funktionalitet kan påverka allt som är kopplat mot det och ge upphov till grövre problem för systemet i helhet. Generellt är underhåll avsystem,som är kritiska att vara funktionella,ett växande forskningsområde somutvecklas. Inom kraftelektroniken krävs det mer forskninggällandesystemets hälsa och vad som orsakaratt systemets funktionalitet misslyckas. Detta examensarbete syftar tillatt efterforska vad som orsakar att kraftelektroniska systemet misslyckas och hur dessa orsaker kan förhindras.Utöver detta är ett sensorbaserat system utvecklat för att samla data som anses vara relevanta för livslängden av systemet och dess degradering. Dataär behandlad och analyserad med estimeringmetoder relevanta för forskningen.
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Babayan-Aghan, Vahik. "Investigation into different types of single-phase AC/DC convertors." Thesis, Loughborough University, 1995. https://dspace.lboro.ac.uk/2134/7063.
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The work detailed in the thesis compares the performance of single-phase thyristor bridge converters under different control strategies; considering in particular the efficiency, ac side power factor and harmonic content of the current and voltage waveforms. Extensive practical investigations were performed, in which, analogue and digital control circuits were developed to provide the drive signals necessary for a converter to operate in the different control modes for: a) A series -connected fully-controlled double thyristor bridge (used mainly in traction applications) operating under sequence control and; b) A fully controlled single-bridge operating under sequence and conventional control. A novel pulse-width modulation control strategy was developed for the single-bridge converter, using gate turn-off thyristors as the switching elements, whereby output voltage control is obtained by variation of the modulation index. Turn-on and turn-off signals for the power devices were obtained using an analogue control circuit. The advantages and disadvantages of this switching strategy compared with conventional and sequence control were studied, and results clearly showed that an improved input power factor and lower supply current and load voltage harmonics were all obtained. Mathematical models for single and double bridge converters operating under sequence and conventional control were developed using tensor techniques. Using these models, computer programmes were written in Fortran 77 on the University mainframe computer, to assemble automatically and solve the network equations as the converter topology changes. In addition, analytical models were also developed on the assumption that the load current is completely smooth. However, such an assumption is not justifiable with ac-to-dc converters and consequently a novel technique was developed to include the load current ripple in calculating the supply current harmonics. The results obtained are compared with both the computed and experimental ones.
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Louganski, Konstantin. "Generalized Average-Current-Mode Control of Single-Phase AC-DC Boost Converters with Power Factor Correction." Diss., Virginia Tech, 2007. http://hdl.handle.net/10919/27331.
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The dissertation presents a generalized average-current-mode control technique (GACMC), which is an extension of the average-current-mode control (ACMC) for single-phase ac-dc boost converters with power factor correction (PFC). Traditional ACMC is generalized in a sense that it offers improved performance in the form of significant reduction of the current control loop bandwidth requirement for a given line frequency in unidirectional and bidirectional boost PFC converters, and additional functionality in the form of reactive power control capability in bidirectional converters. These features allow using a relatively low switching frequency and slow-switching power devices such as insulated-gate bipolar transistors (IGBTs) in boost PFC converters, including those designed for higher ac line frequencies such as in aircraft power systems (360â 800 Hz). In bidirectional boost PFC converters, including multilevel topologies, the GACMC offers a capability to supply a prescribed amount of reactive power (with leading or lagging current) independently of the dc load power, which allows the converter to be used as a static reactive power compensator in the power system.
A closed-loop dynamic model for the current control loop of the boost PFC converter with the ACMC has been developed. The model explains the structure of the converter input admittance, the current phase lead phenomenon, and lays the groundwork for development of the GACMC. The leading phase admittance cancellation (LPAC) principle has been proposed to completely eliminate the current phase lead phenomenon and, consequently, the zero-crossing distortion in unidirectional converters. The LPAC technique has been adapted for active compensation of the input filter capacitor current in bidirectional boost PFC converters.
The dynamic model of the current control loop for bidirectional boost PFC converters was augmented to include a reactive power controller. The proposed control strategy enables the converter to process reactive power and, thus, be used as a reactive power compensator, independently of the converter operation as an ac-dc converter.
Multiple realizations of the reactive power controller have been identified and examined in a systematic way, along with their merits and limitations, including susceptibility to the ac line noise. Frequency response characteristics of reactive elements emulated by means of these realizations have been described.
Theoretical principles and practical solutions developed in this dissertation have been experimentally verified using unidirectional and bidirectional converter prototypes. Experimental results demonstrated validity of the theory and proposed practical implementations of the GACMC.
Ph. D.
8
Daniele, Matteo. "A single-stage power factor corrected AC/DC converter." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/tape17/PQDD_0018/MQ39474.pdf.
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Mino, Kazuaki. "Novel hybrid unidirectional three-phase AC-DC converter systems /." [S.l.] : [s.n.], 2009. http://e-collection.ethbib.ethz.ch/show?type=diss&nr=18185.
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Woods, Joseph. "The parallel connection of single phase DC to AC power converters." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp01/MQ39102.pdf.
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Ismail, Nasser. "A single stage full bridge power factor corrected AC/DC converter." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/mq26004.pdf.
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Alam, Md Muntasir Ul. "Investigation of bridgeless single-phase solutions for ac-dc power factor corrected converters." Thesis, University of British Columbia, 2017. http://hdl.handle.net/2429/62355.
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In modern power supplies and battery chargers, a front-end power factor correction (PFC) AC-DC converter is used to comply with regulatory requirements for input current harmonics. The prevalence of standards and recommended practices to meet harmonic current limits has gained, and continues to gain, momentum over recent years. Additionally, the improvement of overall converter efficiency is critical for the emergence and acceptance of these converter technologies, to meet the standard of efficiency and power factor requirements.
This dissertation presents some innovative solutions for bridgeless non-isolated and isolated PFC AC-DC converters. All proposed converter solutions realize bridgeless converter operation to reduce conduction losses and operate in hybrid resonant pulse-width-modulation (HRPWM) mode. The PWM switches share the same gating signal, so the converter does not need extra circuitry to sense the positive and negative ac input line-cycle operation.
The first contribution is a non-isolated bridgeless AC-DC converter, which has inherent inrush current-limiting capabilities. The converter architecture also enables simple implementation of lightning and surge protection systems. Moreover, this converter can survive sustained over-voltage events and can limit the voltage stress on the converter and downstream components.
The second contribution is a non-isolated bridgeless AC-DC converter, which realizes soft-switching operation to reduce switching losses. This converter can operate at high switching frequency to increase power density.
The third contribution is a three-level non-isolated bridgeless AC-DC converter, which has high voltage gain. This converter also provides soft-switching operation of all the power devices. Due to the three level architecture, all commutations occur with a voltage level equivalent to half the output voltage, which further reduces switching losses. This converter can utilize lower voltage rated devices, which reduces system cost.
The final contribution is a single-stage bridgeless isolated AC-DC converter. This converter shows low conduction loss due to bridgeless operation and low voltage stress of the secondary diodes, low switching loss due to soft-switching operation, and a transformer that has no dc magnetizing current and does not store energy. These characteristics minimize the transformer size and increases transformer efficiency.Applied Science, Faculty of
Engineering, School of (Okanagan)
Graduate
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Chen, Fang. "Control of DC Power Distribution Systems and Low-Voltage Grid-Interface Converter Design." Diss., Virginia Tech, 2017. http://hdl.handle.net/10919/77532.
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DC power distribution has gained popularity in sustainable buildings, renewable energy utilization, transportation electrification and high-efficiency data centers. This dissertation focuses on two aspects of facilitating the application of dc systems: (a) system-level control to improve load sharing, voltage regulation and efficiency; (b) design of a high-efficiency interface converter to connect dc microgrids with the existing low-voltage ac distributions, with a special focus on common-mode (CM) voltage attenuation.
Droop control has been used in dc microgrids to share loads among multiple sources. However, line resistance and sensor discrepancy deteriorate the performance. The quantitative relation between the droop voltage range and the load sharing accuracy is derived to help create droop design guidelines. DC system designers can use the guidelines to choose the minimum droop voltage range and guarantee that the sharing error is within a defined range even under the worst cases.
A nonlinear droop method is proposed to improve the performance of droop control. The droop resistance is a function of the output current and increases when the output current increases. Experiments demonstrate that the nonlinear droop achieves better load sharing under heavy load and tighter bus voltage regulation. The control needs only local information, so the advantages of droop control are preserved. The output impedances of the droop-controlled power converters are also modeled and measured for the system stability analysis.
Communication-based control is developed to further improve the performance of dc microgrids. A generic dc microgrid is modeled and the static power flow is solved. A secondary control system is presented to achieve the benefits of restored bus voltage, enhanced load sharing and high system efficiency. The considered method only needs the information from its adjacent node; hence system expendability is guaranteed.
A high-efficiency two-stage single-phase ac-dc converter is designed to connect a 380 V bipolar dc microgrid with a 240 V split-phase single-phase ac system. The converter efficiencies using different two-level and three-level topologies with state-of-the-art semiconductor devices are compared, based on which a two-level interleaved topology using silicon carbide (SiC) MOSFETs is chosen. The volt-second applied on each inductive component is analyzed and the interleaving angles are optimized. A 10 kW converter prototype is built and achieves an efficiency higher than 97% for the first time.
An active CM duty cycle injection method is proposed to control the dc and low-frequency CM voltage for grounded systems interconnected with power converters. Experiments with resistive and constant power loads in rectification and regeneration modes validate the performance and stability of the control method. The dc bus voltages are rendered symmetric with respect to ground, and the leakage current is reduced. The control method is generalized to three-phase ac-dc converters for larger power systems.Ph. D.
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Musavi, Fariborz. "Investigation of high performance single-phase solutions for AC-DC power factor corrected boost converters." Thesis, University of British Columbia, 2011. http://hdl.handle.net/2429/35082.
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Plug-in Hybrid Electric Vehicles (PHEVs) and Electric Vehicles (EVs) are an emerging trend in automotive circles, and consumer’s interest is growing rapidly. With the development of PHEVs, battery chargers for automotive applications are becoming a large market for the power supply industries. The improvement of overall charger efficiency is critical for the emergence and acceptance of these vehicular technologies, as the charger efficiency increases, the charge time and utility cost decreases. Additionally, to meet the efficiency and power factor requirements and regulatory standards for the AC supply mains, power factor correction is essential.
Due to limited space in vehicle and increasing power consumption, chargers are required to deliver more power with smaller volume. As a key component of a charger system, the frontend
AC-DC converter must achieve high efficiency and high power density. In this dissertation, several conventional plug in hybrid electric vehicle charger front end AC-DC converter topologies are investigated and a new bridgeless interleaved and a phase shifted semi-bridgeless power factor corrected converter are proposed to improve the efficiency and performance, which is critical to minimize the charger size, charging time, and the amount and cost of electricity drawn from the utility. A detailed analytical model for these topologies is developed, enabling the calculation of power losses and efficiency. Experimental and simulation results of several prototype boost converter converting universal AC input voltage to 400 V DC at 3.4 kW are given to verify the proof of concept, and analytical work reported in this thesis. The results show a power factor greater than 0.99 from 750 W to 3.4 kW, THD less than 5% from half load to full load and a peak efficiency of 98.94% at 265 V input and 1200 W load.
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Danko, Donald. "Configurable Frequency and Voltage Three Phase Power Supply." Wright State University / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=wright1559166225004371.
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Rashid, Tariq. "Perturbation model based analysis of a three phase PWM ac-dc power converter." Thesis, University of Bristol, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.336819.
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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.
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Rustom, Khalid. "STEADY STATE AND DYNAMIC ANALYSIS AND OPTIMIZATION OF SINGLE-STAGE POWER FACTOR CORRECTION CONVERTERS." Doctoral diss., University of Central Florida, 2007. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/2216.
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With the increased interest in applying Power Factor Correction (PFC) to off-line AC-DC converters, the field of integrated, single-stage PFC converter development has attracted wide attention. Considering the tens of millions of low-to-medium power supplies manufactured each year for today's rechargeable equipment, the expected reduction in cost by utilizing advanced technologies is significant. To date, only a few single-stage topologies have made it to the market due to the inherit limitations in this structure. The high voltage and current stresses on the components led to reduced efficiency and an increased failure rate. In addition, the component prices tend to increase with increased electrical and thermal requirements, jeopardizing the overarching goal of price reduction. The absence of dedicated control circuitry for each stage complicates the power balance in these converters, often resulting in an oversized bus capacitance. These factors have impeded widespread acceptance of these new techniques by manufacturers, and as such single stage PFC has remained largely a drawing board concept. This dissertation will present an in-depth study of innovative solutions that address these problems directly, rather than proposing more topologies with the same type of issues. The direct energy transfer concept is analyzed and presented as a promising solution for the majority of the single-stage PFC converter limitations. Three topologies are presented and analyzed based on this innovative structure. To complete the picture, the dynamics of a variety of single-stage converters can be analyzed using a proposed switched transformer model.Ph.D.
School of Electrical Engineering and Computer Science
Engineering and Computer Science
Electrical Engineering PhD
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Ho, Wen-Jung, and 何文榕. "Optimizing Single-Phase AC/DC/AC Converter with PFC-Preregulator Improvement." Thesis, 1997. http://ndltd.ncl.edu.tw/handle/30363357595270470618.
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博士國立臺灣大學
電機工程學系
85
The research of the dissertation focuses on the topologies of single-phase AC/DC/AC converter with pre-staged power-factor- correction (PFC). In the beginning, new topologies for PFC- prestaged AC/DC/AC converter are presented. The introduction of common-neutral connection simplifies the conventional connection of AC/DC/AC structure, and gives new topologies that still have good performance, conform with output safety regulations and have other advantages such as requiring fewer power devices and having loweconduction losses. Then a new on-line uninterruptible power supply (UPS) structure is also presented. It consists of a dual-functional PFC substituting for an inevitable battery- voltage booster thereby simplifying the complexity of power stage. Finally an even simpler topology of power stage for UPS applications is to be shown. This new single-conversion UPS mainly consists of a minimized power converter structure which is capable of providing specified constant output voltage, phase-controlled battery charr, and input-power-factor improvement.
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Dharmarajan, Vimala. "Three-level soft-switched DC-to-DC converter and single-phase, single-stage, three-level AC-to-DC converter." Thesis, 2006. http://hdl.handle.net/1828/2335.
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This thesis proposes a three-level DC-to-DC converter with capacitive output filter and its extension to single-phase, single-stage, three-level AC-to-DC converter with capacitive output filter. The AC-to-DC converter integrates a three-level boost converter operating in discontinuous conduction mode (DCM) and a three-level half-bridge DC-to-DC converter with capacitive output filter.
The steady-state operation of the DC-to-DC converter and AC-to-DC converter with capacitive output filter are studied with phase-shifted gating scheme. The three-level topology reduces the voltage rating of the switches to half of the input voltage. Soft-switching is achieved for switches at different load and input voltage conditions. Boost section of the AC-to-DC converter achieves automatic power factor correction (PFC). At reduced load and higher input voltage conditions, the line current Total Harmonic Distortion (THD) increases with phase-shifted gating scheme. The THD has been reduced by using a complementary PWM gating control in the AC-to-DC converter.
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Hung, Ming-Fu, and 洪銘福. "The Design and Application of the Three Phase AC-DC Converter Simplified to the Single Phase DC-DC Converter." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/cc5m7n.
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碩士國立臺北科技大學
電機工程系研究所
97
Three-phase AC-DC converters are gradually and widely being used in industry mainly for the improvement of the quality of the input current and adjust the magnitude of output voltage. By using the switch, the voltage and current on the input side are adjusted to be in-phase. As more and more types of three-phase AC-DC circuit topologies have been invented, usually the three-phase AC-DC converters are analyzed through the D-Q transformation. In the D-Q domain, the State Space equation are mutually coupled, thus the design of the control system is still difficult and complicated. In references, usually only the small signal equivalent model, the transfer function and the controller design of single-phase DC-DC converters are described in detail. However, the study of those for the three-phase AC-DC converter has not been dealt with in depth. The object of this paper is to propose a simplified method for modeling the three-phase AC-DC converters in order to extensively apply the knowledge of single-phase DC-DC converters to the simplified modeling of three-phase AC-DC converters. The paper shows that after the simplification is completed, the principles which work for single-phase DC-DC converter are able to be applied to the simplification model of three-phase AC-DC converter as well. The paper would be a helpful reference to people who need to design and analyze the control systems of the three-phase AC-DC converter.
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Liaw, Gin Tu, and 廖金塗. "MODELING AND IMPLEMENTATION OF A SINGLE PHASE AC/DC CONVERTER." Thesis, 1993. http://ndltd.ncl.edu.tw/handle/63600535296434779074.
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Shie, Wei-Meng, and 謝唯盟. "A Novel Single-Phase Multilevel Current Source DC-AC Converter." Thesis, 2004. http://ndltd.ncl.edu.tw/handle/10465687388776835280.
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碩士國立清華大學
電機工程學系
92
Multilevel converters are usually used in high power applications to reduce the voltage and current stress of the active switches and meanwhile to achieve better output waveform quality. Recent researches are basically focused on the voltage source multilevel dc to ac converters. Concerning the multilevel current source dc to ac converters, only very few papers are available in the literature. In view of this, the main purpose of this thesis is focused to the study of single-phase current source dc to ac converters. The contributions of this thesis may be summarized as follows. First, a novel configuration of single-phase multilevel current source dc to ac converter is proposed to achieve better performance as compared with that of the existing literature. Second, operation principles of both five-level and seven-level configurations are presented. It turns out that the proposed multilevel configuration can be extended to ( ) level as well as three-phase system easily. Third, a simple carrier signal synthesis technique is proposed to obviate using many logic gates for getting the desired carrier signal. Hence, by comparing the modulating signal with the carrier signal, one can obtain the switching signal easily and more reliably. Fourth, the proposed multilevel converter cannot only be used to generate clean sinusoidal output current but also can be used to track other nonsinusoidal command signals. In other words, it can be used as a low frequency power amplifier. Finally, a prototype is also constructed and experimental results are presented to verify the feasibility of the proposed converter.
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HU, SHU-YU, and 胡書瑜. "Realization of Three-Phase AC-to-DC Converter with Single-Phase Modules." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/9q962x.
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碩士南臺科技大學
電機工程系
106
This thesis presents a study of three-phase AC-DC conversion using three sets of single-cycle controlled based single-phase AC-DC converters, and each output is cascaded by a full-bridge DC-DC converter. The proposed input side includes three sets of single-phase AC-DC converters with Y-type connection, and their output are following with three sets of full-bridge phase-shift converters in parallel connection on the output side to complete the three-phase AC-DC conversion. The proposed AC-DC converter adopts single-cycle control based method to implement the power factor correction function. This method is easy and convenient than the traditional control method. The traditional method needs to detect the mains voltage, and the design of the sensing element is relatively complex when the input voltage is relatively high. The presented single-cycle control adopted in this This study discusses the input voltage control method for the three AC/DC converters on the input side, and the current sharing control method for full-bridge DC/DC converters in the output side. Finally, three sets of total 1500W systems are used to verify the proposed idea is feasible.
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Chao, Kuo-Hen, and 趙國亨. "Low Frequency Ripple Compensation Methods for Single-Phase AC/DC Converter." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/76634933535763114118.
Full textAbstract:
碩士國立清華大學
電機工程學系
97
This thesis presents five power decoupling methods of single phase AC/DC converters using three switch poles to achieve unity power factor operations. The methods proposed compensate the pulsating power at twice the grid frequency by circulating the reactive power through the power decoupling capacitors between the third switch pole and DC bus. This approach can eliminate the need of large filter capacitor in DC side which is required to suppress the low frequency ripples. This thesis will explain the principles of operations of the proposed methods, and experimental results will also be presented for validation.
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Wu, Che-Wei, and 吳哲維. "Study of a High Performance Single-Phase AC to DC Converter." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/03528683928252552788.
Full textAbstract:
碩士國立宜蘭大學
電機工程學系碩士班
96
A high performance single-phase AC to DC converter is proposed in this thesis. Basically the proposed converter is an integration result of a power factor correction circuit with a dc-to-dc converter to achieve simple hardware circuit, high efficiency, and low cost. A novel two-switch Cuk converter operates as an ac-to-dc converter with sinusoidal input current, unity power factor, and low ripple dc output voltage. Since both the input boost supply and the output supply can be controlled independently, a fast transient response can be maintained at both the input for active current waveshaping and at the output for good output regulation. Finally, some simulation and experimental results are presented for verification.
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陳昭立. "Study of a High Power Factor Single-Phase Boost AC-DC Converter." Thesis, 2001. http://ndltd.ncl.edu.tw/handle/37602045494445347540.
Full textAbstract:
碩士國立成功大學
工程科學系
89
Because of the need for high quality power, the harmonic standards are becoming stricter. Because the diode rectifier is ineffective in this higher standard, many theorems have been developed to improve the current waveforms. In general the advantage of hysteresis current control is that the current error can be kept within certain limit. However, the switching frequency is uneven and random, causing excessive stress on the switching device. The filter is also difficult to design. PWM methods with fixed switching frequency can reform current waveforms and have good response to load variations, but few studies have been conducted on the current error. The switching algorithm for a single-phase boost AC-DC converter is proposed in this thesis. The relation between the current error and switching period was developed. For a limit current error, the maximum switching period for an AC-DC converter can be achieved to reduce the switching loss and deliver nearly sinusoidal current waveforms with unity power factor. The proposed scheme was implemented using a 32-bit digital signal processor TMS320C32, analog to digital converter and digital to analog converter. Simulations and experimental results demonstrate the feasibility and fast dynamic response of the proposed control strategy.
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Tsai, Wei Che, and 蔡維哲. "Analysis and Design of Single-Phase Bipolar Voltage Switching DC-AC Converter." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/11636705527367712422.
Full textAbstract:
碩士東海大學
電機工程學系
100
In this paper we present the design and through the TSMC 0.25μm HV process to achieve a single-phase bipolar voltage switching DC-AC inverter. The design of the main structure is PWM bipolar switching technology and a level shift circuit connect to full-bridge circuit to do the DC input voltage to the AC output voltage control. A supply voltage and temperature-independent bandgap reference circuit is used in the inverter that has a output voltage of 9.4V/60Hz of sine wave. The AC sine wave voltage is provided to a small AC LED load. The chip area is 1.9 x 2.05mm2. Circuit simulation verifies the performance and feasibility of the conversion system.
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Chen, Li Chung, and 陳立中. "Implementation of a single-phase DC/AC converter with power decoupling capability." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/05939419653712461220.
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SHEN, HONG-REN, and 沈鴻任. "New Three-port DC-AC Power Converter Outputting a Single-Phase and a Three-Phase Sinusoidal AC Voltages." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/30468808611251815777.
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Qiu, Jain-Yao, and 邱建堯. "Parallel Control of Single Phase DC to AC Converters." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/82952884560914331605.
Full textAbstract:
碩士國立清華大學
電機工程學系
93
Abstract The application of single-phase DC to AC converters is quite popular. However, due to the limited voltage/current rating of power semiconductor components, the capacity of a single inverter is also constrained. A simple strategy to increase the output power capacity is by parallel operation of several inverters. In fact, the content of this thesis is focused on the research of parallel control techniques. Basically, the major contributions of this thesis may be summarized as follows. First, a novel control strategy is proposed to enhance greatly the dynamic performance of a single inverter. Only simple proportioned controls are adopted for the voltage regulator and the current regulator as well as for the feedforward and feedback controllers. The enhanced dynamic performance can be observed clearly from the transient response to a nonlinear load. Second, based on the previous control, a novel parallel control strategy is proposed to achieve the goal of uniform sharing of the output current for each inverter. Again, in addition to the uniform current sharing characteristic, the merits of fast response and with zero steady state error of a single inverter control can be preserved for the compound system. Finally, a prototype system is successfully constructed by using a high speed digital signal processor, namely DSPTMS320F2812. Experimental results show that the proposed parallel control strategy can indeed achieve the desired performance.
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Siao, Kun-Cheng, and 蕭琨澄. "Single-phase Bi-directional AC/DC Converter with Power Factor Correction and Phase-Locked Loop." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/14660587232864353104.
Full textAbstract:
碩士國立中山大學
電機工程學系研究所
102
With the development of smart grids, more and more Distributed Generation Systems (DGSs) and Renewable Energy Generation Systems (REGSs) will be interconnected to power grids in the foreseeing future. Most of DGSs and REGSs are DC power sources; therefore, power inverters are used to convert DC power of DGSs and REGSs to AC powers and to interconnect to power grids. In addition, most of REGSs are unstable power sources; they require Energy Storage Systems (ESSs) to stabilize output power. The ESSs can be charged by the REGSs and by power grids if necessary, so the design and development of a bi-directional AC/DC converter is necessary. This thesis develops and implements a single-phase bi-directional AC/DC converter with power factor correction and phase-locked loop. A fully digital controller for the implemented 1kW bi-directional AC/DC converter is designed by Microchip dsPIC33FJj16GS504. Experimental results show that the proposed single-phase bi-directional AC/DC converter can not only has rated power of 1kW but also achieve power factor correction and phase-locked loop.
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HSU, JUI-PO, and 徐瑞柏. "Three-phase Impedance-Source Bidirectional AC/DC Converter." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/n5b7ft.
Full textAbstract:
碩士國立臺灣科技大學
電子工程系
105
In this thesis, the topology of three-phase AC-DC converters is studied. An impedance source (Z-source) topology together with traditional three-phase six-switch circuit to achieve the buck/boost function in single-stage structure. Traditional voltage source or current source inverter has the limitation that output voltage can only be less than or greater than the input voltage. The impedance source topology has combination of inductors, capacitors, and one auxiliary switch. The input port is neither a voltage source nor a current source. Therefore, the output voltage can be either higher or lower than the input. Besides, eliminating the potential hazard of short-through or open-circuit in voltage-source or current-source circuits, Z-source circuit possesses better reliability. In one of the two operation modes, the auxiliary switch can be passively mode, resulting an easier control mechanism. The control algorithm for a Z-source can be an extension based on convention control algorithm. This thesis implements a three-phase Z-source AC-DC converter with input voltage of 150 V and 200 V, output voltage of 110 Vrms and 500 W output power. According to the test results, it is confirmed that the effect can be buck/boost in single-stage structure.
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Zargari, Navid Reza. "A novel high performance current regulated DC/AC converter for single phase and three phase systems." Thesis, 1990. http://spectrum.library.concordia.ca/4599/1/MM64754.pdf.
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Liu, Hsing-Fu, and 劉興富. "Novel Single-Phase Single-Stage AC/DC Converters with Input Current Shaper." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/70858281911225827342.
Full textAbstract:
博士國立交通大學
電機與控制工程系所
93
This dissertation presents a new input current shaper (ICS) for single-phase single-stage AC/DC converters with harmonic current correction and fast output voltage regulation. The proposed ICS are applied in flyback structure, forward structure, and bridge structure with the function of harmonic current correction. All the circuits are analyzed in steady state consideration. The study contains operation principle analysis, critical parameters analysis, design procedure. Finally, simulations and experiment results are shown for verifications. In the proposed AC/DC converters, an extra winding wound in the transformer provides two key advantages: (i) The size of the bulk inductor used in the conventional boost-based PFC cell can be significantly reduced in the proposed converters. In same output power application, the main transformer should has similar size but the boost inductor in prior single-stage PFC converter will be up to 1.7Lm or 1.4mH, and the inductor L1 in the proposed circuit can be down to 0.1Lm or 30μH. (ii) The voltage across bulk capacitor can be held under 450V by tuning the transformer windings ratio even though the converter operates in a wide range of input voltages (90V~265V/ac). Similar technique has been reported in recent years, but complex control circuit is needed to achieve high power factor or still use a bulk inductor in the boost-cell in the front stage of the converter. In a competitive market of switching power supply, the main consideration includes a simple, reliable, and cost-effective. Therefore, there is an improved opportunity in those presented solutions. These new converters comply with IEC 61000-3-2 class D from the load range up to 600W, and can achieve fast output voltage regulation. The proposed circuit has a simple, reliable, and cost-effective structure. The switching frequency is fixed in the proposed converters, which benefits the design of transformer and EMI filter. The proposed solution employs conventional controller, UC3842 or TL494, to implement the circuits and the solution can comply with the agent’s standards.
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Chen, Yan-Ming, and 陳彥名. "Efficiency Analysis of a Single-Phase AC/DC Converter and its Power Decoupling Circuit." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/08074079210558647676.
Full textAbstract:
碩士國立清華大學
電機工程學系
99
This thesis compares three kinds of power decoupling circuits of single phase AC/DC converters .The converters have Power factor correction and bidirectional power flow capability and compensate the pulsating power at twice the grid frequency by power decoupling circuits. In order to improve the overall efficiency of DC/AC converter, an overall power loss analysis was conducted. The proposed methods compensate the pulsating power at twice the grid frequency by circulating the reactive power through power decoupling capacitor; the capacitance which used in dc bus can be eliminated. The elaborate calculation of conduction loss, switching loss, reverse recovery loss, copper loss, and core loss are presented to give a quantitative analysis of power loss, through losses analysis to choose the suitable switches and use optimal inductance to improve efficiency. This thesis will explain the principles of operations of the proposed methods, and experimental results will also be presented for validation.
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Chen, Yo-Ming, and 陳佑民. "Simulation and Analysis of Digitally Controlled Single-Phase Full-Bridge PWM AC-DC Converter." Thesis, 2001. http://ndltd.ncl.edu.tw/handle/42279849350484417633.
Full textAbstract:
碩士國立交通大學
電機與控制工程系
89
This thesis presents the simulation and analysis in power factor correction, output voltage regulation and power flow for full-bridge switching mode rectifier（SMR）. The circuit operation of the full-bridge SMR circuit is introduced first, and then the pulse width modulation is analyzed. Finally the output voltage, input inductance and dc-BUS capacitance are derived as a basis for the selection of the input inductor and output capacitor. This thesis applied the PSIM simulation software to generate a digital control full-bridge SMR model and a closed control loop. To simulate and analyze the results in different switching modes and different conditions including changing load, varying input voltage, the PFC for regeneration mode load, output voltage regulation and the power flow in SMR converter. The simulation results can be take as a reference for implementing DSP based digital control circuit.
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Ciou, Yi-Fan, and 邱逸凡. "A Single-phase Full-bridge Boost-buck AC/DC Converter with Adjustable Power Factor." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/38752q.
Full textAbstract:
碩士國立虎尾科技大學
電機工程研究所
97
This thesis presents a novel single-phase full-bridge AC/DC converter is constituted by combining a single-phase full-bridge power circuit with and a DC SEPIC converter. Basically, it has several advantages such as boost/buck voltage, sinusoidal input current, adjustable power factor and low switching losses etc. A generalized zero vector(GZV) technique is applied to the proposed converter, such that the power circuit is integrated into a single stage. Digital control of the converter is implemented by VisSim software and TI DSP TMX320F2833 chip. Some advantages, such as small size, easy revision for parameters, and development with less cost, are achieved. Furthermore, use of the dead-band control strategy reduces effectively the switching loss of power switches. Besides, transfer function for both middle-capacitor voltage to duty cycle and output voltage to duty cycle is derived. On the other hand, circuit response of the converter is simulated using MATLAB. Moreover, some experimental results are also presented for verification.
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Liao, Jen-Chuan, and 廖仁詮. "Design of a Single-Phase High Input Power Factor and Low Voltage Regulation AC-DC-AC Power Converter." Thesis, 1996. http://ndltd.ncl.edu.tw/handle/71901152293071288265.
Full textAbstract:
碩士大同工學院
電機工程學系
84
The purpose of this thesis is to analyze and design a new single-phase ac-dc-ac converter with high input power factor and low voltage regulation features. The system consists of a ac-dc switch-mode rectifier and dc-ac full bridge inverter. A switch-mode rectifier employing a voltage reversal circuit is proposed, in which the dc link voltage is superposed on the input voltage at the on-time duration of the power-switching device, and uses active waveshaping method to reduce the input current distortion caused by the small supply voltage at heavy load condition. In addition, by using feedback control to compensate the voltage drop on the output inductor reduces the influence of the inverter output impedance to achieve low voltage regulation. A single-chip microcontroller (80C196 KC) is used to implement the control methods of the proposed system. Experimental results justify the input and output performance of the proposed system that will be better than the conventional four types of converter.
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Li, Mao-Shun, and 李茂順. "Design and Implementation of a Single-Stage Three-Phase High Power Factor AC-DC Converter." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/15540894482618974959.
Full textAbstract:
碩士國立成功大學
電機工程學系碩博士班
96
In this thesis, a single-stage high power factor three-phase AC-DC converter is proposed. The proposed converter is composed of a three phase AC-DC buck/boost converter integrated with a DC-DC buck-boost converter. The front semi-stage circuit is used for power factor correction and the rear semi-stage circuit is used for DC-DC conversion. The proposed converter can achieve unity power factor with a simple control and structure. The operation principles and characteristics of the proposed converter are discussed. Finally, the single-stage power supply of 500W is performed with a line input voltage of 200 Vrms 10% and DC output 48V/500W is performed in the laboratory to verify the feasibility of the proposed converter.
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Fang, Kuan-Hui, and 方冠輝. "Study of Novel Soft-switching Technologies Used in Single Phase Isolated PFC AC-DC Converter." Thesis, 1994. http://ndltd.ncl.edu.tw/handle/81856898456075148251.
Full textAbstract:
碩士國立成功大學
電機工程研究所
82
Traditionally,the AC-DC converter used a passive rectifier, add large capacitor,but it will produce an amount of input current harmonics,These large input current harmonics will make not only the power factor but also the power quality is poor,so in this thesis will use a average current mode control to make the unity power factor,and use a feedforward method make the output voltage has a better dynamic response when the input voltage various.For safty ,in the proposed converter a isolated high frequency transformer is used.In this thesis ,the proposed converter used a boost type push- pull converter to achieve our goal.For increasing the efficiency a novel soft-switching technologies is used to reduce the switching losses.Finally,a single-phase 1KVA push-pull boost converter is setup to verify the predicted and analyzed result. The experimental result show that the proposed push-pull converter has unity power factor, high power conversion efficiency,small size,light weight,low THD,low EMI and fast transient response.
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Ding, Pei-Lun, and 丁培倫. "A Novel Single-Phase Half-Bridge AC/DC Converter with Regeneration and Adjustable Power Factor." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/zy23gw.
Full textAbstract:
碩士國立虎尾科技大學
電機工程研究所
98
The thesis proposes a novel single-phase half-bridge AC/DC converter with energy regeneration and adjustable power factor. Based on a generalized zero vector technique , the novel single-stage converter of AC to DC consists of a single-phase half-bridge boost rectifier and a buck converter. The proposed converter has several advantages such as input current sinusoidal waveform, energy regeneration and adjustable power factor etc.. By TI TMS28335 DSP and Vissim Embeded control software the digital control circuit is achived. To detect output voltage and input current, current harmonic and power factor can be improved. Furthermore, both DC and small signal mathmatic models of the proposed converter are established to obtain system transfer function. Finally, some experimental results are presented to verify the effectiveness of the proposed converter.
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Yeh, Yu-Ting, and 葉昱廷. "A Single-phase DC-AC Converter with High Dynamic Response and Bi-directional Power Flow Control." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/4sfwp7.
Full textAbstract:
碩士國立臺北科技大學
電機工程系研究所
99
This paper is aimed to design a single-phase DC- AC converter with bi-directional power flow control. The converter is implemented by a full-bridge circuit with bipolar PWM control to act as grid-connected inverter or provide transient current to non-linear load to reduce AC voltage harmonics. A power device with both motoring and generating mode is connected to DC link and controls power flow between power device in DC-side and power grid in AC-side of the proposed DC-AC converter according to DC link voltage. The converter becomes DC-AC converter and sends the energy generated by the power device to electric grid when the DC-link voltage is higher than default voltage command. As the DC link voltage is less than default voltage command, the proposed converter withdraws power from electric grid to the power device. Meanwhile, the converter also provides near unity power factor control for electric grid in the bi-directional power flow control. In order to enhance light-load efficiency of the proposed converter when send the energy to electric grid, an integral-cycles injection of current is developed. When the generated power is less than a preset value, the energy will be stored in the electrolytic capacitance installed in the DC link and all the power switches of full-bridge circuit are turned off. In the need of high dynamic response for AC power supply with line frequency transformer as isolated output, the AC-side of the proposed converter is connected to output of the line-frequency transformer. The converter co-works with the AC power supply and provides extra transient current, which is determined by the difference between AC voltage command and actual voltage of load, for the nonlinear loads to compensate the voltage distortion. Therefore, output voltage harmonics of the AC power supply can be reduced dramatically to meet the requirement of regulations. A single-phase full-bridge DC-AC converter controlled by a DSP-TMS320F28035 with 110V/1 kW is constructed. To realize the digital power control, all the controlling strategies are written by software. Some experimental results are provided to show its efficiency.
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Hsu, Ming-Jun, and 許銘圳. "Study and Implementation of a DSP-Based Single-Phase Active Power Factor Correction AC/DC Converter." Thesis, 2003. http://ndltd.ncl.edu.tw/handle/95431676306573326421.
Full textAbstract:
碩士國立雲林科技大學
電機工程系碩士班
91
This thesis presents a DSP-based fully digital-controlled single-phase power factor converter (PFC). The proposed PFC controller consists of an inner current-loop controller and an outer voltage-loop controller. The current-loop controller adopts hysteresis current control to achieve power factor correction. The voltage-loop controller employs a PI controller to achieve output voltage regulation. This paper adopts TMS320F240 digital signal processor (DSP) as the controller to achieve high power factor, low steady-state error, output voltage regulation, phase- locked loop and parallel operation. Finally, an experimental test was carried out on a 500 W PFC converter using DSP controller and the experimental results verify the feasibility and superiority of the proposed digital AC/DC converter.
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Shu, Kuei-Yuan, and 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.
Full textAbstract:
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.
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Chi, Pei-Chin, and 紀培錦. "A Grid-Tie Control Scheme and Efficiency Optimization for Single-Phase DC/AC Voltage-Sourced Converter." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/df8aqh.
Full textAbstract:
博士國立臺灣科技大學
電子工程系
105
Single-phase distributed power generation system enables renewable energies to be distributed over residential sites and transfers the generated electricity to utility grid, wherein it is usually with direct-current (DC) and alternating-current (AC) grids interfaced by a DC/AC converter which converts and flows the electricity between the grids. To reduce harmonic current and simplify the grid-tie control (GTC), this study proposes a voltage-oriented control scheme for four-quadrant grid-tie of a single-phase DC/AC voltage-sourced converter (VSC) to operate smartly at modes of unity power factor rectifier, inverter, or static VAR compensator. The proposed GTC, in system view, reduces harmonic current and enhances the quality and efficiency for power transfer. Nonetheless, in component view, Metal-Oxide-Semiconductor Field-Effect Transistor (MOSFET) can be utilized to raise switching frequency while Zero Voltage Switching-Clamped Voltage (ZVS-CV) technique eliminates switching loss. Then, heat sink and filter can both be shrunk so that compact VSC can fit the single-phase system in residential site. In order to ensure the ZVS-CV operation, the energy-storing choke of VSC must flow high ripple current that trades off conduction loss of MOSFETs, it motivates this study to propose strategies to optimize the ripple current and efficiency. Simulations and experiments are conducted with a One-Cycle controlled full-bridge VSC to verify the proposed GTC and evaluate its performance for 110 V AC grid under 2 A. Simulations are conducted to compare efficiencies of the 220 V AC inverters about 1 kW load with and without the proposed optimization strategies.
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Lu, An-Sheng, and 呂安生. "A Single-Phase Full-Bridge AC/DC Converter with Bidirectional Power Flow and Adjustable Power Factor." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/73eavd.
Full textAbstract:
碩士國立虎尾科技大學
電機工程研究所
99
This thesis proposes a single-phase full-bridge AC/DC converter with bidirectional power flow and adjustable power factor. Based on a generalized zero vector technique, the proposed AC/DC converter combines a single-phase boost rectifier and a buck-boost converter into a single-stage AC/DC converter. The proposed converter has several advantages such as energy regeneration, sinusoidal waveform and adjustable power factor in the input. TI DSP TMS28335 chip and Vissim Embeded control software are both employed to achieve digital control requirement.The advantages of the converter include small size and easy adjustment for control parameters. Detecting output voltage, intermediate capacitance voltage, input voltage and current reaches relative control parameters. A derived modulation function is applied to control circuit, then the converter has faster response, and the advantages mentioned above. Furthermore, both DC and small signal mathematic models of the proposed converter are established to obtain the system transfer function. Finally, some experimental results, such as steady-state response and dynamic response are presented to verify the effectiveness of the proposed converter.
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Juan, Yu-Ling, and 阮昱霖. "An Integrated High Performance Three-Phase Boost AC/DC Converter." Thesis, 2003. http://ndltd.ncl.edu.tw/handle/84966863796430683917.
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Chuang, Fu-Pao, and 莊富堡. "Modeless Predictive Current Control for Three-Phase AC/DC Converter." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/n2r699.
Full textAbstract:
碩士國立臺北科技大學
電機工程系電力電子產業研發碩士專班
103
The objective of this thesis is to design and implement a three-phase AC/DC converter controlled by modeless predictive current control. The special features of the modeless predictive is to predict the optimal switching states in compliance with the cost function using the sensed current while not requiring the converter model. Only addition and subtraction operations are used, neither multiplication nor division operation is required, the implementation is simplified. Moreover, since converter model is not required in the presented modeless predictive control method, the impact of converter parameter can be significantly reduced. A prototype is realized with the following specifications: input voltage = 220 V/AC, output voltage = 380 V/DC. And the output power is 1000 W. A DSP, Renesas SH7216 is used as the controller to realize the presented modeless predictive current control in software. Both simulation and experimental results demonstrate that the input harmonics meet the IEC61000-3-2 Class A and output voltage can be well regulated and thereby confirming the effectiveness of the presented control technique and design of three-phase AC/DC converter.
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CHENG, YU-CHEN, and 鄭宇辰. "Modeless Predictive Current Control for Three-Phase AC/DC Converter." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/t2p644.
Full textAbstract:
碩士國立臺北科技大學
電機工程系電力電子產業碩士專班
108
The main purpose of this thesis is to realize the application of three-vector duty cycle modulation modeless predictive current control on three-phase AC/DC converter. Traditional modeless predictive current control senses the amount of current change and uses a minimum cost function to predict a single optimal switching state within a single duty cycle. However, since only one switching state is used in one sampling period, the current tracking performance is limited. The three-vector duty cycle modulation modeless predictive current control consists of two adjacent effective vectors and one invalid vector. Three different modulation cycles and switching states are applied and sampled during a single duty cycle, and three different modulation cycles and switch states used during the next duty cycle are predicted. The control core used in the experimental system in this thesis is the digital signal processor TMS320F28379D, and is implemented in a fully digitalized control mode. The results confirm that the three-phase AC/DC converter using the modelless three-vector duty cycle modulation predictive current control has better current tracking performance than the conventional one.