Dissertations / Theses on the topic 'Switching at zero voltage'
To see the other types of publications on this topic, follow the link: Switching at zero voltage.
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 50 dissertations / theses for your research on the topic 'Switching at zero voltage.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse dissertations / theses on a wide variety of disciplines and organise your bibliography correctly.
1
Jeong, Timothy. "Zero Voltage Switching Hybrid Voltage Divider Converter." DigitalCommons@CalPoly, 2021. https://digitalcommons.calpoly.edu/theses/2290.
Full textAbstract:
This project proposes a new hybrid voltage divider DC-DC converter that utilizes switching capacitors and inductors to produce zero voltage switching (ZVS) at the turn on state of its switches. By achieving ZVS, the switching losses are significantly reduced; thus, increasing the overall efficiency of the converter at various loads. The goal for this thesis is to perform analysis of the operation of the converter, derive equations for sizing the main components, and demonstrate its functionality through computer simulation and hardware prototype. Results of the simulation and hardware testing show that the proposed converter produces the desired output voltage while providing the zero voltage switching benefits. The converter’s efficiency reaches above 92% starting from 1A load and continues to increase to 97.6% at 4A load. Overall, results from this thesis verifies the potential of the proposed converter as an alternative solution to achieve a very efficient DC-DC solution when half of the input voltage is required at the output without the use of complex feedback control circuitry.
2
Xi, Youhao. "Zero voltage switching flyback and forward converter topologies." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp01/MQ40214.pdf.
Full text
3
Luc, Brian R. "Digitally Controlled Zero-Voltage-Switching Quasi-Resonant Buck Converter." DigitalCommons@CalPoly, 2015. https://digitalcommons.calpoly.edu/theses/1346.
Full textAbstract:
ABSTRACT
Digitally-Controlled Two-Phase Zero-Voltage-Switching Quasi-Resonant Buck Converter
Brian Luc
This thesis entails the design, construction, and performance analysis of a digitally-controlled two-phase Zero-Voltage Switching Quasi-Resonant (ZVS-QR) buck converter. The converter is aimed to address the issues associated with powering CPUs operating at lower voltage and high current. To evaluate its performance, the Two-Phase ZVS-QR buck converter is compared against a traditional Two-Phase buck converter. The design procedure required to implement both converters through utilizing the characterization curve and formulas derived from their circuit configurations will be presented. Computer simulation of the Two-Phase ZVS-QR buck converter is provided to exhibit its operation and potential for use in low voltage and high current applications. In addition, hardware prototypes for both ZVS-QR and traditional buck converters are constructed utilizing a Programmable Interface Controller (PIC). Results from hardware tests demonstrate the success of using digital controller for the 60W 12VDC to 1.5VDC ZVS-QR buck converter. Merits and drawbacks based on the operation and performance of both converters will also be assessed and described. Further work to improve the performance of ZVS-QR will also be presented.
Keywords: Buck Converter; Zero-Voltage-Switching; Multi-Phase; Efficiency; Switching Loss
4
Choi, Jae-Young. "Analysis of Inductor-Coupled Zero-Voltage-Transition Converters." Diss., Virginia Tech, 2001. http://hdl.handle.net/10919/28537.
Full textAbstract:
As is the case for DC-DC converters, multi-phase converters require both high-quality power control and high power-density. Although a higher switching frequency not only improves the quality of the converter output but also decreases the size of the converter, it increases switching losses and electromagnetic interference (EMI) noise. Since the soft-switching topologies reduce the switching losses of the converter main switches, the topologies make converters partially independent from the switching frequency. However, the conventional soft-switching topologies have already proposed most of the possible ways to improve converter performance. In addition, the trends of the newly generated power devices reduce the advantages of soft-switching topologies. This critical situation surrounding soft-switching topologies gives research motivations: What features of soft-switching topologies facilitate their practical applications? Given this motivation, the dissertation discusses two aspects = simplifying auxiliary circuits and accounting for the effects of soft-switching operations on the converter control.
Engineers working with medium- and high-power multi-phase converters require simplified soft-switching topologies that have the same level of performance as the conventional soft-switching topologies. This demand is the impetus behind one of the research objectives = simplifying the auxiliary circuits of Zero-Voltage-Transition (ZVT) inverters. Simplifying the auxiliary circuits results in both a smaller number of and lower cost for auxiliary components, without any negative impact on performance. This dissertation proposes two major concepts for the simplification - the Single-Switch Single-Leg (S3L) ZVT cell and the Phase-Lock (PL) concept.
Throughout an effort to eliminate circulating currents of inductor-coupled (IC) ZVT converters, the S3L ZVT cell is developed. The proposed cell allows a single auxiliary switch to achieve zero-voltage conditions for both the top and bottom main switches, and it achieves the same level of performance as the conventional ZVT cell, as well. This proposal makes IC ZVT topologies more attractive to multi-phase converter applications.
Because all of the top main switches generally have identical sequences for zero-voltage turn-on commutations, one auxiliary switch might handle the commutations of all of the top main switches. This possibility introduces the PL concept, which allows the two auxiliary switches to provide a zero-voltage condition for any main switch commutation. In order to compensate for restrictions of this concept, a modified space-vector modulation (SVM) scheme also is introduced.
A soft-switching topology changes the duty ratios of the converter, which affects the controllability of the converter. Therefore, this dissertation selects resolution of this issue as one of the research objectives. This dissertation derives the generalized timing equations of ZVT operations, and the generalized equations formulize the effect of ZVT operation on both duty ratios and DC current. Moreover, the effect of SVM schemes is also investigated. An average model of the ZVT converter is developed using both the timing analysis and the investigation of SVM schemes, and small-signal analysis using the average model predicts the steady-state characteristics of the converter.Ph. D.
5
Hua, Guichao. "Novel zero-voltage switching techniques for pulse-width-modulated converters." Thesis, This resource online, 1991. http://scholar.lib.vt.edu/theses/available/etd-03242009-040340/.
Full text
6
Musabeyoglu, Ahmet Can. "A zero-voltage switching technique for high frequency buck converter ICs." Thesis, Massachusetts Institute of Technology, 2017. http://hdl.handle.net/1721.1/113122.
Full textAbstract:
Thesis: M. Eng., Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, 2017.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Cataloged from student-submitted PDF version of thesis.
Includes bibliographical references (pages 59-60).
This thesis explores a zero-voltage switching (ZVS) method that can be used to decrease the frequency dependent losses in a buck converter. The specific application for this thesis was a buck converter IC with an input voltage of up to 42V. The method utilizes the addition of an auxiliary circuit composed of a helper inductor and two helper power MOSFETs that compliment the switching transition of a conventional synchronous buck converter topology. It is shown in this thesis that by using the described topology, the switching losses of the high-side power MOSFET in a synchronous buck converter can be reduced by up to 45%. Furthermore, it is shown that a similar helper circuit could be used to reduce the gate drive losses for both power MOSFETs in a synchronous buck converter by up to 60%. Since the method requires the use of an additional helper inductor with a small value (10-50 nH), various methods to integrate this inductor into an IC package are investigated. 0.35[mu]m BiCMOS technology was used to simulate and analyze the merits of the described topology and compare it to the LT8697, a hard-switched synchronous buck converter IC.
by Ahmet Can Musabeyoglu.
M. Eng.
7
Jain, Nikhil. "A zero voltage switching boost converter using a soft switching auxiliary circuit with reduced conduction losses." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2001. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/MQ59306.pdf.
Full text
8
Mao, Hengchun. "Soft-switching techniques for high-power PWM converters." Diss., This resource online, 1996. http://scholar.lib.vt.edu/theses/available/etd-10052007-143055/.
Full text
9
Cliffe, Robert J. "High power high frequency DC-DC converter topologies for use in off-line power supplies." Thesis, Loughborough University, 1996. https://dspace.lboro.ac.uk/2134/7305.
Full textAbstract:
The development of a DC-DC converter for use in a proposed range of one to ten kilowatt off-line power supplies is presented. The converter makes good use of established design practices and recent technical advances. The thesis begins with a review of traditional design practices, which are used in the design of a 3kW, 48V output DC-DC converter, as a bench-mark for evaluation of recent technical advances. Advances evaluated include new converter circuits, control techniques, components, and magnetic component designs. Converter circuits using zero voltage switching (ZVS) transitions offer significant advantages for this application. Of the published converters which have ZVS transitions the phase shift controlled full bridge converter is the most suitable, and assessments of variations on this circuit are presented. During the course of the research it was realised that the ZVS range of one leg of the phase shift controlled full bridge converter could be extended by altering the switching pattern, and this new switching pattern is proposed. A detailed analysis of phase shift controlled full bridge converter operation uncovers a number of operational findings which give a better and more complete understanding of converter operation than hitherto published. Converter design equations and guidelines are presented and the effects of the new improvement are investigated by an approximate analysis. Computer simulations using PSPICE2 are carried out to predict converter performance. A prototype converter design, construction details and test results are given. The results obtained compare well to the predicted performance and confirm the advantages of the new switching pattern.
10
Kang, Wen. "A line and load independent zero voltage switching dc/dc full bridge converter topology." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2001. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/MQ59307.pdf.
Full text
11
Gall, Jonathan Henrik. "Zero-Voltage-Switching PWM Full-Bridge Converter for Onboard Charging of Battery of Electric Vehicles." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2019.
Find full textAbstract:
This thesis gives a description of working principles of a Phase-Shifted Full-Bride PWM ZVS converter using a Full-Wave rectifying output as well as a Double Current Rectifier. After a description of each topology and some differences between the two topologies, a hybrid solution is presented. The hybrid configuration is a combined FW and DCR, in an interleaved connection. By the opening and closing of a switch that is located between the two output stages, either a DCR-DCR or DCR-FW rectifying output stage is used for the converter. This allows for dynamic turns ratio of the step-up transformer of the converter, as well as reduced primary and secondary side currents.
The voltage for when to switch between the two output configurations is derived analytically. Simulations carried out in LTSpice to verify the analytical results and the hypothesis of reduced currents and losses are presented in the end.
12
Hunter, Daniel Scott. "Variable-frequency pulse-width-modulation for zero-voltage switching in a boost DC-DC regulator." Thesis, Monterey, California. Naval Postgraduate School, 1990. http://hdl.handle.net/10945/37543.
Full textAbstract:
Approved for public release; distribution is unlimited.A technique for operating a pulse-width-modulated (PWM) dc-dc regulator in the boost mode while switching the MOSFET when the drain-to-source potential is near zero volts was developed and is described in this thesis. This is accomplished by using frequency-modulation in addition to pulse-width-modulation. Zero-voltage switching will provide power converter designers an alternative for designing high-frequency converters with minimal transient turn-on losses, the predominant form of converter losses experienced in high frequency operation. High frequency operation will result in smaller reactive components, which produce higher power density converters, as well as increasing the transient response of the regulated converter. In addition to allowing for high frequency operation, the design exhibits many desirable power switch properties, such as limiting the peak voltage to the output voltage level and operating with the minimum possible current levels for a given power requirement. A circuit built and tested utilizing zero-voltage switching in a regulated boost converter verified the principles of operation for yielding a high-efficiency, high-frequency converter.
13
Hsieh, Jen-Chung, and 謝荏仲. "Zero Voltage Zero Current Switching Three Phase Voltage Relay." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/f7vs63.
Full textAbstract:
碩士聖約翰科技大學
電機工程系碩士班
106
The project presents a new three phase voltage protection relay, which use PIC18F27J13 microcontroller to implement the main protection function of the relay such as incorrect phase sequence, overvoltage, undervoltage, phase failure, asymmetry etc. In addition to these functions, we add on the adjustment of the switching phase angle of the relay contactor. While the relay is turn on at zero voltage and turn off at zero current, the spark of the contactor will be eliminated and the power dissipation is reduced, also the EMI is reduced and relay life is extended.
14
Chiang, Chu-Yi, and 姜柱圯. "Lowest-Voltage-Switching and Zero-Voltage-Switching Control for Buck Converter." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/68830049900111453144.
Full textAbstract:
博士國立臺灣大學
電子工程學研究所
97
A new integrated circuit approach for Lowest-Voltage-Switching and ZVS control is presented for PWM buck converters under DCM/CCM boundary mode. This proposed technique compensates control circuit delay and hence turns on the power MOS at the exact instant of lowest/zero drain-to-source voltage. No complicated timing calculation circuits or additional external components are required. This proposed integrated Lowest-Voltage-Switching and ZVS control can be applied to other DC-DC converters as well. Circuit analysis, implementation and the die photo are shown. Experimental results for an example circuit with VIN of 5V and VOUT of 1.8V and 3.3V reveal that buck converters with the presented Lowest-Voltage-Switching and ZVS technique have higher efficiency than conventional ones, especially at higher frequencies. At about 1.35MHz and 3.6MHz operation, the measured conversion efficiency of the PWM buck converter under DCM/CCM boundary mode with the proposed Lowest-Voltage-Switching and ZVS approach is 9% and 11% higher, respectively. Also, the replenishing scheme for the holding capacitor in sample and hold circuit is designed and simulated. Its operation is analyzed and simulation results are illustrated. Furthermore, buck converter with synchronous rectifier and its related ZVS gating control is presented. Analysis and simulation results are conducted and shown.
15
張家瑞. "Zero-Voltage-Switching Series-Resonant High-Voltage Inverter." Thesis, 2002. http://ndltd.ncl.edu.tw/handle/82267723066081338597.
Full textAbstract:
碩士國立臺灣科技大學
電子工程系
90
A zero-voltage-switching series-resonant inverter (ZVS-SRI) is proposed for ozone generation to increase the efficiency of ozone production. A pulse-density modulation (PDM) control strategy is adopted as the series-resonant drives with ZVS to program the power delivery to the ozonizer. Description of the configurations and basic principle of the ZVS-SRI is conducted to build up a simple design criterion and realization methodology. A design consideration for implementing the ZVS-PDM SRI for the ozonizer is proposed. A design example is examined with experiment and simulation for verifying the theoretical prediction. The experiment shows that the proposed ozonizer with unprocessed air input can provide ozone output of 26.2g/kWh and the production modulation range is widen between 8~100%.
16
Hsu, Ting-Chuan, and 許丁泉. "Zero-Voltage-Switching Interleaved DC/DC Converter." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/32964201312058939292.
Full textAbstract:
碩士雲林科技大學
電機工程系碩士班
97
An interleaved DC/DC converter with less power switches is presented in this thesis. Two forward converter cells are connected in parallel and unite common power switches without using extra switching devices to achieve the features of interleaving and zero-voltage-switching (ZVS). Active-clamping circuit is adopted at the primary side of transformers to circulate the energy stored in magnetizing inductor and leakage inductor of transformers and reduce the switching losses and noises on power switches. In addition, the paralleling manner with interleaving technique has shared the output current and diminished its ripple effectively. Principles of operation, steady state analyses and design procedure are explained. Finally, experimental results with a 75W prototype circuit are provided to verify the analysis.
17
Su, Peng-Yu, and 蘇鵬宇. "Interleaved Flyback Converters with Zero-Voltage Switching." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/20305064192950453900.
Full textAbstract:
碩士義守大學
電機工程學系
102
This thesis proposes a novel dc-to-dc converter that consists of two interleaved flyback converters with zero-voltage switching-on characteristic. Both flyback converters use power MOSFETs as the active switches. With no need to use any components for active-clamping circuit or snubber circuit, both active switches can operate at zero-voltage switching-on(ZVS) by freewheeling the converter current through the body diode of the MOSFET. The switching losses can be effectively reduced, thus improving the overall circuit efficiency. As compared with traditional flyback converter, the interleaved converter has the advantages of lower current and voltage ripples. It helps to reduce the voltage and current stresses on the circuit components, leading to increase the circuit reliability. The steady-state analyses for different operation modes are provided and the mathematical equations for designing circuit components are conducted in this thesis. Finally, a 200-W prototype circuit was built and tested to verify the feasibility of the proposed circuit. Base in the experimental results, both active switches actually operate at ZVS. The proposed circuit is with satisfactory performance and the measured circuit efficiency is 91.3%.
18
TA, HAN YUNG, and 韓永達. "Zero-Voltage-Switching Boost Power Factor Corrector." Thesis, 2000. http://ndltd.ncl.edu.tw/handle/10020135739104244683.
Full textAbstract:
碩士國立臺灣科技大學
電子工程系
88
This thesis presents a zero-voltage-switching (ZVS) technique that eliminates recovery problem in the boost switch and significantly reduces its switching losses to lengthen its life with using soft switching technique.The method allows a PFC which operates at higher frequencies with great efficiency and reduced EMI.The thesis uses average-current mode control,operating at a fixed switching frequency,to reduce line harmonics and to improve power factor.A lead-lag compensator which we use to compensate the ZVS PFC;besides,its controls,design procedures and ZVS timing diagram are also introduced.A ZVS PFC is designed to illustrate the theoretical estimation with the specifications: =90~265VAC/60Hz, =380 , =1000W, =100KHz, > 0.96、Power Factor > 0.95.Besides,a hard switching PFC is also made in order to compare their differences.The experimental result is so close to the theoretical prediction. keywords：soft switching,power factor,ZVS,PFC,average-current mode
19
孫淑媛. "Implementation of the Zero Voltage Switching Relay." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/31340141128381173707.
Full textAbstract:
碩士國立彰化師範大學
電機工程學系
99
Nowadays, relay plays an important role in the necessary components of automatic equipment. The operation principle of relay is that it will produce the electromagnetic effect and attract magnets to the core after coil of Relay is electrified. On the other hand, once the power supply is removed from the coil of relay, the magnets will break off when the electromagnetic attraction disappears, and therefore to achieve the goal of controlling electric equipment with relay. However, when Relay is conducted or turned off, there are several problems will come after, such as the contact of Relay will produce spark easily, the contact will oxidize and bring dust. Moreover, the life time and reliability of device will be reduced after all. In this thesis, Zero Voltage Switching (ZVS) relay is proposed to reduce the phenomenon of spark discharge. To utilize the ZVS function, the zero voltage signal of the grid is detected by Micro Controller, and turn on/off relay during the zero voltage region. First, the turn on/off switching time is tested and recorded, whose is required for adjusting the parameter in microcontroller. While user conducts and cuts off the signal, microcontroller will enable/disable relay to control relay on/off. Finally, the experiment result reveals the proposed method is feasible, while resistance load is applied to the circuit.
20
Chang-HungChien and 簡彰宏. "Zero-voltage Switching Resonant Converters for High Input Voltage Applications." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/68802191506397652260.
Full textAbstract:
博士國立成功大學
微電子工程研究所碩博士班
101
In this dissertation, three novel zero-voltage switching resonant converters are proposed. The proposed converter 1 and converter 2 combine two parallel resonant converter cells by operating with an interleaved half switching cycle to allot the input current equally on active switches, and to mitigate the root-mean-square (rms) current on primary windings such that the copper losses of transformers and the size of the magnetic core are reduced. Using the complementary circuit modules to transport the energy lessens the ripple current on the input capacitor such that the capacitance is reduced. Therefore, those topologies defeat the high current stress of passive and active component disadvantage of formal LLC resonant converter for high power. By incorporating the two series half-bridge legs and two split capacitors to limit the stress voltage of active switches within a half input voltage, two high 480V to 600V input and 24V/40A output resonant converters for high input voltage applications are demonstrated. To balance the secondary winding currents and share the load currents, the series-parallel connected transformers are adopted in converter 1. Not only is the heat effectively relieved, but also is higher efficiency performed due to the less switching and conduction losses. Besides, the series–series connected transformers are adopted in converter 2 to balance the primary and secondary winding currents. Not only is the heat effectively relieved, but only four rectifier diodes are also used as replacement of the eight features in terms of low cost, small size, and light weight. The average active-mode efficiency of converter 1 and converter 2 are above 90.5 % and 88 %, respectively. Moreover, a novel DC/DC converter with cascode two circuit modules for high input voltage application is researched in converter 3. The converter combines two series resonant converter cells by operating with an interleaved one-fourth switching cycle to allot the input current equally on active switches. Using the interleaved circuit modules to transport the energy lessens the ripple current on the input and output capacitors such that the capacitance is reduced. The primary windings of two transformers are connected in series to balance the secondary winding currents, and the secondary windings of two transformers are connected in parallel to reduce the current stresses on the secondary windings. The average active-mode efficiency is above 92 %. On the other hand, the voltage stress of the rectifier diodes in those topologies are almost clamped to twice the output voltage, rather than being more than twice that of asymmetrical half-bridge converters. Thus, low voltage rating Schottky or ultra-fast diodes are used in the second side to reduce cost. To decrease the reverse recovery losses of rectifier diodes, the switching frequency at full load is designed to be lower than the series resonant frequency. The high input voltage applications include three-phase 380V utility system, ship electric power distribution system, server power supply, data storage system, and fuel cell system.
21
PENG, CHANG-YI, and 彭常益. "A Three-Phase Six-Switch Rectifier with Zero-Voltage-Switching and Zero-Current-Switching Features." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/68662627484730364292.
Full textAbstract:
碩士中原大學
電機工程研究所
98
Since the requirements for both regulation and standard on power quality and current harmonics are more strict in recent years, many switch mode rectifier techniques are widely adopted. There are many different kinds of basic types for switch mode rectifier. Three-phase six-switch topology in three-phase supply power system is often used in the equipment of the communication industry due to the facts that it has better power quality, lower current harmonics, and higher reliability; also, it is suitable for need in high power application. Adopting hard switching in switch mode power supply technology would cause low efficiency and high electromagnetic interference. In this thesis, there is an analysis and design for a soft-switching scheme that contains zero voltage switching and zero current switching. This analysis and the design combined with a three-phase six-switch topology rectifier creates a new three-phase soft-switching rectifier which would have characteristics of stable output voltage, high efficient, high power density, high power factor, and low electromagnetic interference.
22
Agelidis, Vassilios G. "Zero voltage switching pulse width modulated inverter topologies." Thesis, 1991. http://spectrum.library.concordia.ca/5578/1/MM73683.pdf.
Full text
23
Chen, Yung-Chang, and 陳泳嶂. "A Novel Zero-Voltage-Switching Loaded-Resonant Converter." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/31968135923827461260.
Full textAbstract:
碩士崑山科技大學
電機工程研究所
99
In the currently known converters, the class E resonant converter is the most efficient one, and different combinations of resonant inductance and resonant capacitance inside the resonant trough of the resonant converter can produce different resonance effects, so that when the resonant converter power switch is operated at zero voltage switching (ZVS) or zero current switching (ZCS), the losses due to power switch on-and-off can be reduced, and the converter efficiency is thus enhanced, to avoid unnecessary waste of energy. Presented in this paper is the novel zero-voltage-switch loaded resonant converter whose power switch can be operated at a zero voltage switching (ZVS) mode to reduce the switching losses so as to improve the converter efficiency. This new converter needs only a single power switch as well as a single set of driving signals, while the traditional class D resonant converter needs two power switches and two sets of driving signals, which inevitably results in higher production costs and won’t be able to reach the expected circuit efficiency. As a result, this paper is for the development of the novel low-cost and high efficient zero-voltage-switch loaded resonant converter.
24
Ma, Tsung-Heng, and 馬宗亨. "E-Type Resonant Converter with Zero-Voltage-Switching." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/bdx5pt.
Full textAbstract:
碩士崑山科技大學
電機工程研究所
102
The different combinations of the capacitance and inductance in resonant tank can produce different resonant effects and patterns. Besides, a resonant converter can also achieve ZVS(Zero Voltage Switching) or ZCS(Zero Current Switching) at the time of switching, which can reduce switching losses and enhance the efficiency of converters. The class E resonant converter is currently the most efficient among all the converter classes. We can adjust switching frequency to obtain soft-switching and connect two capacitors, instead of two Schottky barrier diode, at the bridge and full wave rectifier. Not only lowering power loss but also achieving double voltage converter in this Paper. Finally, we show fruitful result by proving the efficiency of the improved E-Type Resonant Converter with Zero-Voltage-Switching can reach 98% by loading resonant double converters.
25
Liu, Zhen-Yi, and 劉振億. "Wireless Power Transfer with Zero-Voltage-Switching Converter." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/5733w5.
Full text
26
Huang, Chien-Lan, and 黃建嵐. "The Zero Voltage Switching Active Clamp Cuk converter." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/82422949523497952672.
Full textAbstract:
碩士國立雲林科技大學
電機工程系碩士班
95
In this thesis, an active clamp Cuk PWM converter is analyzed for continuous conduction mode (CCM). Cuk topology has gathered more attention in recent years. Base on the continuous input and output current, wide output voltage range and small output filter. The active clamp technique is used to improve circuit efficiency and achieve zero voltage switching (ZVS). In the proposed converter, both main switch and auxiliary switches are soft-switching to increase of the efficiency and increase the power density. Operation principle, design analysis and conditions of zero voltage switching of the power switches are described. Finally, some simulation and experimental results are presented to verify the effectiveness of the proposed converter.
27
Ou, Wei-sheng, and 歐威盛. "Hybrid Zero-Voltage- and Zero-Current-Switching Phase-Shift Full-Bridge Converter." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/85117610964744319402.
Full textAbstract:
碩士國立中山大學
電機工程學系研究所
101
Conventional phase-shift full-bridge converter can achieve Zero-Voltage Switching (ZVS) at power switches by phase shift control of switches’ driving signal. However, the problems such as freewheeling circulating loss, duty cycle loss, parasitic ringing and hard to achieves ZVS in the lagging leg switches at light load still exist in the conventional phase-shift full-bridge converter. Thus the conventional phase-shift full-bridge converter can not be operated efficiently at light load. This thesis implements a hybrid Zero-Voltage and Zero Current Switching (ZVZCS) phase-shift full-bridge converter. An auxiliary resonant circuit is added to the secondary side of the conventional phase-shift full-bridge converter to generate resonant current. Based on the generated resonant current, the ZVS for leading-leg switches and ZCS for lagging-leg switches can be achieved without modifying the original switches’ driving Pulse Width Modulation (PWM) signals. The freewheeling circulating loss, duty cycle loss and parasitic ringing can therefore be reduced. The detailed operation modes and circuit parameters design for the proposed converter are analyzed in this thesis. A circuit prototype for the proposed ZVZCS phase-shift full-bridge converter with rated power 480W is implemented in this thesis. The performances between the conventional phase-shift full-bridge converter and the proposed ZVZCS phase-shift full-bridge converter are also investigated. Experimental results demonstrate the features of the proposed ZVZCS converter.
28
Lo, Shao-Wen, and 羅紹文. "Analysis and Implementation of Zero-Voltage Switching Converter with Output Voltage Doubler." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/55989743458698524819.
Full textAbstract:
碩士國立雲林科技大學
電機工程系碩士班
97
This thesis presents a zero-voltage switching (ZVS) converter with output voltage doubler which consists of two forward converter cells with common power switches to reduce cost and complexity of the circuit topology. The active clamping technique can clamp the voltage stress and create the ZVS conditions on switches. Therefore, the conversion efficiency can be improved. Finally, the circuit operation principle, design considerations, experimental results and simulations are presented to verify the effectiveness of the proposed converter.
29
Pan, Jian-Liang, and 潘建良. "Zero-Voltage-Switching Resonant Converter with Single-Switch Topology." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/23484167168743517285.
Full textAbstract:
碩士崑山科技大學
電機工程研究所
100
In order to achieve the goal of a high performance, low switching loss, high efficiency, and low cost electric converter. In this thesis, using two different soft-switching DC resonant converters are applied to resist rectification. There are divided into two parts. First is type single-switch zero voltage switching resonant converter. Second is type single-switch zero voltage switching resonant converter. By using class E resonant converter to be circuit structure gains more advantages such us, smaller volume, lighter weight, simple circuit structure, high output efficiency, as well as lower cost. The class E resonant converter is the most efficient one and the circuit structure is simple than before. It is different from the traditional class D resonant converter, even higher efficiency is, and also only need a set of power switch and a set of driving signal circuit. It can not only reduce the cost, but also can use the simple circuit structure to reach the efficiency. While in the resonant converter, using the different elements of arranging combination in the resonant circuit will gain different results of resonance. This thesis adopting two different kinds of resonant circuits, one is series, and the other is series-parallel, and also using soft-switching of zero voltage switching (ZVS) to solve the losses caused by switching. This method can easily improve the efficiency of the converter, and also avoid unnecessary waste of energy. By this situation of switching conduction, to analyze of the principles of circuit workmanship and the mode of operation, to build the same effects of circuit, to devise the resonant in best component parameter, and also use computer simulation and practical circuit to verify the theory. In conclusion, the researching result of typeⅠuni-switch zero voltage switching resonant converter and typeⅡuni-switch zero voltage switching resonant converter, both two kinds of DC resonant converter circuit of efficiency can reach higher than ninety-six percentage.
30
Chen, Chang-jung, and 陳常榮. "Zero-Voltage-Switching Resonant-Switch Converters for Battery Chargers." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/95138927098569427635.
Full textAbstract:
碩士國立臺灣海洋大學
電機工程學系
100
The main purpose of this thesis is to research and develop two different kinds of battery chargers of resonant-switch converters. Starting with the zero voltage switch (ZVS) and the converters, which employ the quasi-resonant converter (QRC) technique,we gain the best parameters of the resonance components from the characteristic curve diagrams of these two converters. Then we design battery chargers based on these two structures and use them to experiment on lead-acid batteries. According to experiments, the battery charger with the zero voltage switch quasi-resonant converter (ZVS-QRC) is turned on and turned off at the point of zero voltage, while the one with the zero current switch quasi-resonant converter (ZCS-QRC) is turned on and off at the point of zero current. The result proves that both chargers reach the resonance-switched standard. Moreover, when compared with the charger with the traditional pulse-width-modulation (PWM) converter,the charger with ZVS or ZCS quasi-resonant converters indeed lowers the temperature of the switch, resulting in the reduction of switch losses. Subsequently, in this thesis we combine the zero voltage transition (ZVT) soft-switched buck converter with the pulse-width modulation and the resonance technology to maintain constant operation frequency. It is an effective way to reduce the switch loss of the traditional hard-switching converter, filling the requirement that all circuit components are zero voltage switched ones. In the meanwhile, two clamping diodes can be used to lengthen the resonance period, and prevent the peak value of resonance capacitance and resonance inductance from exceeding the voltage stresses and current ones in the traditional pulse-width-modulation converter. Therefore, we develop a lead-acid battery charger on the basis of the zero voltage transition soft-switched theory. According to the result of experiments,when compared with the traditional pulse-width-modulation converter, the zero voltage transition soft-switching buck converter can indeed lower the temperature of the switch, reduce the switch losses and stresses, lengthene the lives of components, improve the whole efficiency, and further prolong the life of lead-acid battery
31
Huang, Chien-En, and 黃乾恩. "Implementation of Zero-voltage-switching Converter with Active-Clamp." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/97361511430585935911.
Full textAbstract:
碩士國立雲林科技大學
電機工程系碩士班
93
The objective of this thesis is to design and implementation of Zero-Voltage-Switching Converter with Active-Clamp topology. The energy stored in the magnetizing and leakage inductance can be retrieved to improve the efficiency by the active-clamped circuit. On the other hand, the active-clamp circuit can help the main switch to be operated at zero voltage switch, in order to reduce the switching losses of main switch. In order to increase the efficiency, a synchronous rectifier is adopted by using MOSFET with low Rds(ON) at the output end. The drive signal of synchronous rectifier switch is come from the transformer secondary side voltage in order to reduce the complexity of driven circuit designed. Finally, the design of the zero-voltage-switch Forward and Flyback converters with active clamp reset and synchronous rectification are proposed. A design example of AC/DC converter, whose input range from 90Vac~132Vac and the output 5V/20A is presented.
32
Lin, Shu-Jung, and 林樹榮. "Analysis and Implemetation of Zero Voltage Switching Zeta Converter." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/42683105674286572254.
Full textAbstract:
碩士國立雲林科技大學
電機工程系碩士班
95
Switching Mode Power Supplies (SMPS) are widely used in business market. The system analysis, circuit design and implementation of an active-clamp isolated Zeta converter with buck-boost type are presented in the paper. Active clamp circuit is used in the conventional isolated Zeta converter to recycle the energy stored in the leakage inductor and magnetic inductor of transformer. The resonant circuit including the leakage inductor and magnetic inductor of transformer, parasitic capacitors of main power switch and a clamp capacitor can achieve ZVS turn-on condition. Therefore hard-switching converter high switching losses, noise and high voltage stress in the conventional hard switching converter can be improved. The Performance of the proposed isolated Zeta converter with buck-boost type of active clamp is compared with conventional hard-switching Zeta converter in the paper. The experiments verify the effectiveness of the proposed Zeta converter.
33
Huang, Feng-Yu, and 黃豐裕. "A ZERO VOLTAGE SWITCHING HALF BRIDGE SERIES RESONANT CONVERTER." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/08347892719042572083.
Full textAbstract:
碩士大同大學
電機工程學系(所)
94
This thesis presents a soft switching half bridge LLC series resonant converter combine the PFC circuit. In resonant converter all switches working on the ZVS and the secondary diodes are working on the ZCS. This topology is very simple just only use one magnetic component to achieve the ZVS. This thesis presents a zero-voltage-switched (ZVS) of resonant half-bridge converter. Its advantages are high efficiency, low EMI, low switching loss, compact size, low voltage stress, etc. To achieves the ZVS of power switches, in front-end used PFC to provide a fixed voltage for the resonant converter. At the same time the PFC also reduces the harmonic current. An experimental prototype of 90~264Vac input, 24V/10A output, the resonant converter full load efficient reaches 95.2%.
34
Shiu, Shin-Ming, and 徐新明. "Analysis and Design of a Novel Interleaved Boost Converter with Zero-Voltage-Switching and Zero-Current-Switching Characteristics." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/80314328637175630676.
Full textAbstract:
碩士國立雲林科技大學
電機工程系碩士班
97
A novel interleaved boost converter with zero voltage switching (ZVS) and zero current switching (ZCS) characteristics is proposed in this thesis. This topology is suitable for the applications of high output voltage and low output current. A prototype converter circuit is given for 150V~250V input voltage and 400V with 200W to 600W output. By the interleaved approach, this topology not only decreases the current stress of the main circuit device but also reduces the ripple of the input current and output voltage. Moreover, by establishing the common soft-switching module, the soft-switching interleaved converter can greatly reduce the size and cost. The main switches can achieve the characteristics of ZVS and ZCS simultaneously to reduce the switching loss and improve the efficiency for wide load range. This topology has two operation conditions if the duty cycle can exceed 50%. The converter should have a resonant path to accomplish ZVS or ZCS in different conditions. A driving circuit design for the proposed topology determines the two conditions automatically according to the overlap condition of the duty cycles of the two switches. The driving signal of the soft-switching module is composed of the ZVS driving signal and the overlap driving signal of the two switches to achieve the functions of ZVS and ZCS. The operational principle, theoretical analysis and design method of the proposed converter are presented. Simulation and experimental results are finally used to verify the feasibility and exactness of the proposed converter.
35
Huang, Shih-Jung, and 黃士榮. "Analysis and Implementation of Zero-Voltage-Switching DC power supply." Thesis, 2004. http://ndltd.ncl.edu.tw/handle/83791236556134123567.
Full textAbstract:
碩士國立雲林科技大學
電機工程系碩士班
92
With the development of power electronic technique, the switching mode power supplies have gradually replaced the linear voltage regulator. Generally speaking, to comply with the international standard, such as IEC555-2 and IEC1000-3-2, the system can be classified into two parts: the power factor corrector circuit as the first stage and the DC / DC converter as the second stage. In this thesis, we discuss the soft switching techniques to reduce the switching losses and increase the system efficiency. Zero voltage switching technique is used in the adopted AC / DC converter to achieve high power factor, low current harmonics, and stable DC bus voltage. For the DC / DC converter the full-bridge phase-shift zero-voltage-transition (FB-PS-ZVT) technique is also used to decrease the switching losses. In order to reduce the conduction losses at the transformer secondary winding, the current doubler rectifier is also adopted for the DC / DC converter to further reduce the losses and increase the system efficiency. Finally the operation principle, design analysis, operating conditions to achieve zero-voltage switching, and the experimental results are described and discussed in the thesis.
36
Wen-Hong, Hwang, and 黃文宏. "Realization Study of Active Clamp Zero-Voltage-Switching Forward Converter." Thesis, 1999. http://ndltd.ncl.edu.tw/handle/52551390082910880017.
Full textAbstract:
碩士國立臺灣科技大學
電子工程系
87
This paper is to present the design and realization of the forward converter with active clamp reset (FACR). The zero-voltage-switching (ZVS) is achieved by a resonant inductor to reduce the switching loss. In order to increase the efficiency, a synchronous rectifier is adopted by using MOSFET with low RDS(ON)(about 10mΩ) at the output end. To further stabilize the system, a voltage mode control with voltage feed-forward is adopted to eliminate the variation of the input voltage variation for reducing the number of variables in the transfer function. This paper first analyzes the operation of the zero-voltage-switching forward converter with active clamp reset and synchronous rectification. The small-signal transfer function is derived for the analysis of frequency response. Both system stability and dynamic response are also conducted. Finally, a design procedure of the zero-voltage-switch forward converter with active clamp reset and synchronous rectification is proposed. A design example of DC/DC converter, whose input is 48V (ranged from 40~60VDC) and the output is 5V/20A, is implemented to verify the computer simulation and the theoretical predictions. 英文摘要 Ⅱ 誌謝 Ⅲ 目錄 Ⅳ 圖表索引 Ⅶ 第一章 緒論 1 1.1 研究動機 1 1.2 研究目的 2 1.3 內容簡介 4 第二章 順向式轉換器的原理 6 2.1 洩磁繞組順向式轉換器 6 2.2 諧振洩磁順向式轉換器 10 2.3 被動式箝位洩磁順向式轉換器 12 第三章 主動式零電壓順向式轉換器分析 16 3.1 動作原理與穩態分析 16 第四章 同步整流電路 30 4.1 同步整流簡介 30 4.2 順向式轉換器同步整流原理 31 第五章 系統分析及補償 34 5.1 系統小訊號分析 34 5.2 控制方式 41 5.3 回授補償技術 43 第六章 設計考量 47 6.1 工作週期 47 6.2 諧振電感設計 47 6.3 變壓器設計 48 6.4 切換功率晶體開關的選用 52 6.5 同步整流開關的選用 53 6.6 切換功率晶體驅動電路的設計 53 6.7 輸出電容、電感的設計 55 6.8 箝位電容的設計 57 第七章 設計實例 60 7.1 工作週期 60 7.2 諧振電感設計 60 7.3 變壓器設計 61 7.4 切換功率晶體開關的選用 62 7.5 同步整流電晶體的選用 62 7.6 切換功率晶體驅動電路的設計 62 7.7 輸出電容、電感的設計 62 7.8 箝位電容的設計 63 7.9 控制器設計 63 第八章 系統模擬 66 8.1 主電路各點波形模擬 66 8.2 IsSpice 模擬結果 67 8.3 提昇IsSpice模擬速度的方法 73 8.4 小訊號模擬 74 第九章 量測與結果 77 9.1 電路實際量測結果 77 9.2 電路實測波形 79 9.3 小訊號量測結果 86 9.4 討論 88 第十章 結論 90 參考文獻 91
37
Tzang, Pei-Jing, and 曾培景. "Boost Converter with Zero Voltage Switching Based on Active Clamping." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/2cz749.
Full textAbstract:
碩士國立臺北科技大學
電力電子產業研發碩士專班
97
A boost converter with zero voltage switching (ZVS) based on voltage clamping is presented herein. With one auxiliary circuit containing a few active and passive devices, the main and auxiliary switches conduct with zero voltage during the turn-on period, so as to reduce the switching loss and electromagnetic interference and hence to upgrade the efficiency and stability of the overall system. first of all, basic operating principles, together with mathematical derivation, are described, and secondly some simulated and experimental results, based on given specifications for one DC-DC converter with 24V input and 42V/100W output, are provided to verify the proposed topology.
38
Chen, Po-Hao, and 陳柏豪. "A Three Phase Interleaved Buck Converter with Zero Voltage Switching." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/72130647854263940655.
Full textAbstract:
碩士國立臺灣科技大學
電子工程系
103
This thesis proposed an interleaved three-phase DC-DC buck converter which is composed of three identical paralleled buck converters. Compared to the conventional paralleled buck converter, the proposed solution has three resonant inductors connected between each other of the three converters. By making use of the principle of quasi-resonant converter, the imposed inductors and the MOSFET parasitic capacitances will resonate to achieve zero-voltage-switching. Besides, the current through the free-wheeling diodes can be zero-current turned off to minimize their reverse-recovery losses. Paralleled topology can help sharing the load currents on each converter and is able to provide higher output power. MOSFETs are controlled by interleaved PWM (Pulse-Width-Modulation) signals to reduce the ripples of input and output currents. Therefore, the filtering capacitances on the input and output sides can be reduced and the power density can be improved. Circuit operation analyses, characteristic equations and simulations are given to understand the circuit. Finally, a 150W three-phase interleaved buck converter is designed, implemented and tested. According to the experimental results, high conversion efficiency over 97 % can be achieved.
39
CHEN, MING-WEI, and 陳明慰. "Analysis and implementation of a zero-voltage-switching buck converter." Thesis, 1992. http://ndltd.ncl.edu.tw/handle/75853593276942817034.
Full text
40
YAN-HUANG, LIM, and 李焉煌. "Half-bridge parallel resonant converter using zero-voltage switching technique." Thesis, 1988. http://ndltd.ncl.edu.tw/handle/28309103926090910186.
Full text
41
Ming-ChiaLee and 李明嘉. "Zero-Voltage and Zero-Current Switching for Multilevel Modular Capacitor-Clamped DC-DC Converter." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/66245999494816756250.
Full textAbstract:
碩士國立成功大學
電機工程學系碩博士班
99
Grouped into two main categories of switched-inductor and switched-capacitor DC-DC power converters, the switching-mode DC-DC power converter is one of the widely used power electronic circuits. With many advantages over the switched-inductor type, the switched-capacitor DC-DC power converter topologies have been widely employed. In this thesis, on the basis of existing topology a zero-voltage and zero-current switching (ZVZCS) scheme for multilevel modular capacitor-clamped DC-DC converter (MMCCC) is proposed and analyzed. The proposed ZVZCS MMCCC circuit features that all switching devices of the circuit can achieve ZVZCS without the need of extra auxiliary switching devices. The proposed ZVZCS MMCCC can eliminate the Miller effect of the power MOSFETs during turn-on operation with the total driving losses reduced. Furthermore, there is no additional voltage and current stress on all switches out of the ZVZCS. A 200 W, four-level, three-module prototype ZVZCS MMCCC circuit has been implemented and verified through simulations and experiments. Superior performance of the proposed circuit to the existing topology has been demonstrated in the thesis.
42
Yeh, Che-Hao, and 葉哲豪. "A 6.78MHz GaN-based Class-E Resonant Wireless Power Transfer System with Automatic Matching Point Searching Control for Zero Voltage Switching and Zero Voltage Derivative Switching." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/vhn2qr.
Full textAbstract:
碩士國立交通大學
電控工程研究所
106
Wireless power transfer system (WPT) technology in recent years gradually improves. A large number of commercial electronic equipment have great demands for high power. Thus, high power and high efficiency become an important issue. WPT system includes transmitter (TX) and receiver (RX). During the transmission, the changes of load and the relative distance affect transmission power and efficiency. Generally speaking, the most common solution is the frequency modulation technique but it contradicts the switching frequency requirement in the A4WP specifications. That is, the modulated frequency is far from the desired switching frequency which is defined as 6.78MHz ± 15kHz. Another intuitive practice is to use a number of compensation capacitors to digitally modulate and achieve the matching requirements corresponding to the variations of WPT system. Unfortunately, in order to resist wide load variation in high power demands, this modulation method must be combined with multiple high voltage switches and compensation capacitors, thereby occupying a larger footprint area and reducing control efficiency. In this thesis, a main structure with a Class-E power amplifier and a Gallium Nitride (GaN) power transistor used at the TX terminal are proposed. The control circuit causes the GaN power transistor to reach zero voltage (ZVS) switching and zero voltage derivative (ZVDS) switching. The power transmission achieves high power and high efficiency simultaneously. Moreover, compared with the state-of-the-arts, due to the voltage controlled compensation capacitor in the analogy modulation method, the control is relatively simple and area efficient.
43
楊岳霖. "Full-bridge phase-shifted zero-voltage and zero-current-switching converter using transformer auxiliary winding." Thesis, 2002. http://ndltd.ncl.edu.tw/handle/16513832659936854844.
Full text
44
夏存孝. "Modeling and Controller Design for Zero-Current-Zero-Voltage-Transition Soft-Switching Boost Power Converter." Thesis, 2001. http://ndltd.ncl.edu.tw/handle/75525304553753788206.
Full textAbstract:
碩士國立成功大學
工程科學系
89
In this thesis, the small signal mathematical model of a zero-current-zero-voltage-transition (ZCZVT) soft-switching boost power converter is proposed, and two controllers are also designed to achieve output voltage regulation. The ZCZVT soft-switching converter is composed of a conventional PWM circuit and a resonant circuit to achieve zero voltage/zero current switching (ZVS/ZCS) and constant frequency operation. This converter overcomes the existing problems of high switching losses of the conventional PWM converters and the conduction losses due to high voltage/current stresses of resonant converters. As a result, ZCZVT soft-switching converters are suitable for high power application system. In the literature, the soft-switching converters were only restricted to DC steady-state analysis. Most of researchers thought that the ac small signal mathematical model should be the same as that of the traditional PWM boost converter. Thus the derivation of the ac model has not been done yet. From the analysis results, the input-to-output voltage conversion ratio of the ZCZVT soft-switching converter depends on load. Moreover, the dynamical behavior will be changed under the variations of load. In this thesis, the averaging method for the two-time-scale discontinuous system (AM-TTS-DS) is used to derive the small signal model of a ZCZVT soft-switching converter. Based on this model, a classical controller and a modified integral variable structure controller (MIVSC) are then designed. The simulation responses and experimental results show that the MIVSC controller has better regulation capacity under the variations of load and line voltage variations than classical controller.
45
Gieun, Hong-June, and 簡鴻鈞. "Design and Implementation of a Zero-Voltage Switching DC Power Supply." Thesis, 2002. http://ndltd.ncl.edu.tw/handle/94400700676775782620.
Full textAbstract:
碩士國立臺灣科技大學
電機工程系
90
Abstract This thesis proposes the design and implementation of a soft switching DC power supply. A full bridge zero-voltage switching DC power supply with a power factor corrector is studied. First, the small-signal models of the boost converter and the phase-shift zero voltage switching converter are proposed. Then, the controllers of the system are designed by using the proposed models. After that, the computer simu-lated programs and hardware circuits are implemented. Finally, several experimental waveforms are measured. The simulated waveforms can validate the measured results.
46
Lin, Wen Cheng, and 林威呈. "Zero-Voltage Switching Power Supply Reliability Analysis and the Associated Verifications." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/02883631415434876029.
Full textAbstract:
碩士元智大學
電機工程學系
94
Reliability is a very important characteristics of lifetime for a product and it must be continuously monitored and controlled to quantitatively measure the state of product after customers start to use this product. In reliability problems, according to the stress-strength principle relationship, we observe the nature behavior of reliability degradation.
47
Huang, Chien-lan, and 黃建嵐. "Analysis and Implementation of Novel Three-level Zero-Voltage-Switching Converter." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/26943888140113270592.
Full textAbstract:
博士雲林科技大學
工程科技研究所博士班
98
This dissertation proposes two kinds of interleaved zero-voltage-switching (ZVS) three-level pulse-width modulation converters with current doubler rectifier. The switches connected in series is adopted to reduce the voltage stress on switches. One fast recovery diode is connected between the middle point of split capacitors and power switch to generate three different voltage levels on the primary side of transformer. All switches can achieve ZVS turn-on at the resonant interval based on the junction capacitance of switches and transformer leakage inductance. Thus the switching losses of power switches can be reduced. The interleaved PWM scheme is used to achieve load current sharing, reduce the ripple current on the input side and regulate the output voltage. The current doubler rectifier is adopted in the secondary side of transformer to reduce the current stress on the transformer secondary winding and achieve the ripple current cancellation on the output capacitor. The advantages of proposed converters are low voltage stresses on switches, low current stresses on switches and diodes and high efficiency. In the dissertation, operation principle, steady state analysis and design consideration of the presented converter are analyzed. Finally, the experimental results are presented to verify the operation principle of the proposed converter.
48
Lin, Cheng-Wei, and 林承緯. "A High-Power-Factor Dimmable LED Driver with Zero-Voltage Switching." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/09798747397966585884.
Full textAbstract:
碩士義守大學
電機工程學系
101
This thesis proposes a novel LED driver consisting of a buck-boost converter and a buck converter. The integrated power conversion circuit adopts two power MOSFETs as the active switches. With no need to use any auxiliary reactive components, both active switches can be operated at zero-voltage switching-on (ZVS) by freewheeling the inductor currents of the converters through the intrinsic diodes of the MOSFETs. The buck-boost converter is operated at discontinuous-conduction mode (DCM) to perform the function of power-factor correction (PFC) to ensure almost unity power factor at the input line. The buck converter steps down the output voltage of the buck-boost converter and regulate the current flowing through LEDs. The detailed circuit operations and analysis are provided. A prototype of a 60-W LED driver is built and tested. Experimental results show that the switching losses can be effectively reduced by operating the active switches at ZVS. The measured power factor and circuit efficiency are as high as 0.995 and 92%, respectively, at the rated power.
49
WANG, Yu-Gu, and 王裕谷. "An Interleaved Zero-Voltage-Switching Power Factor Correction Circuit Applying FPGA." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/m7j863.
Full textAbstract:
碩士國立東華大學
電機工程學系
102
This thesis proposes an interleaved ZVS (Zero-Voltage-Switching) power- factor-correction circuit. FPGA(Field Programmable Gate Array) is applied to coordinate the feedback signals to realize the control algorithm. The power stage is an interleaved boost converter which features not only the merits of interleaved circuits, such as higher current ripple frequency, lower ripple; but also ZVS on active switches, lower switching loss, and higher conversion efficiency from the imposed current swapping inductor. In addition, since the current swapping time is dependent on the input current level, the effective duty ratio and switch on time is also influenced. That is to say, during the line period, effective duty ratio will automatically adjust according to the line voltage varying. Furthermore, the zero-reaching instant of diode current is detected. The active switches are allowed to be gated on after this instant to achieve ZVS. FPGA is applied as the core of control coordination. This choice is due to the future development of application-specific control IC and avoiding the switching frequency limitation of applying single-chip controller. Therefore, ADC conversions are not present in the feedback control loop; instead, all the current command and compensations are realized by analog circuits. The signals sent to FPGA are in on/off state forms. By this way, the lengthy conversion time is avoided, and the switching frequency can be higher during the operation. A prototype circuit is implemented to verify the circuit and the control algorithm. The circuit is fed with 110V line voltage, 400V dc output at 250W power. The input power factor can be higher than 99%. As for FPGA, when final synthesis, only 95 logic units and 63 registers are required to fulfill the control function.
50
Chen, Jun-Han, and 陳俊翰. "Zero Voltage Switching Full-Bridge Converter with Two Different Control Schemes." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/mj3jz3.
Full textAbstract:
碩士國立臺灣科技大學
電機工程系
103
A conventional full-bridge converter has been widely used in high input-voltage, high-power applications. Several control schemes have been applied to full-bridge converter, such as symmetrical control, phase shift control, duty cycle control, and asymmetrical control. Among these, duty cycle control and asymmetrical control have been seldom discussed and will be investigated in this thesis. Employing symmetrical control, full bridge has been used for a long time. It suffers from large switching losses due to its hard-switching operation. It will impact the conversion efficiency and limit power density. To improve the efficiency, phase shift full-bridge converter (PSFB) was successfully proposed instead in the last three decades. Because it can achieve ZVS operation, the switching turn-on losses are significantly reduced. To further improve efficiency, the conduction losses of the rectifier diode can be decreased by employing synchronized rectifier technique. However, two additional driver signals are not available in the popularly used phase shift controllers, such as UC3875 and UC3895. As an alternative control scheme, full-bridge converter with duty cycle control (FBDC) is investigated. In addition to inheriting the advantages and the disadvantages of PSFB, FBDC can directly provide synchronous rectification driver signals if higher efficiency and simple controller design are demanded. However, a circulation loss problem occurs in FBDC as well as in PSFB. Accordingly, a full-bridge converter with asymmetrical control is thus examined. In addition to the descriptions of the operation principle and design consideration, two hardware circuits, FBDC and AFB, with same 300-400-V input and 12-V/ 360W output specifications were built and compared.