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1
Dong, Wei. "The Design of an Asic Control Chip for a Forward Active Clamp Converter and the Investigation of Integratable Lateral Power Devices." Thesis, Virginia Tech, 1997. http://hdl.handle.net/10919/36772.
Full textAbstract:
In Part I, the design of an ASIC control chip for a forward active clamp converter is presented. Integration of the control and drive circuit into one IC chip results in higher power density, higher reliability for the converter module. The designed ASIC control chip uses a 2.0 um N well Analog CMOS process, and is fabricated at MOSIS. The design procedures of the ASIC chip are explained, and experimental results are presented.
Part II of the thesis focuses on the numerical investigation of several integratable lateral power devices. Lateral power devices are used in power IC designs because of their compatibility with analog & digital IC process. To obtain devices with high current density, large safe operating area, fast response and low cost is highly desirable for power ICs. In Part II of this thesis, several lateral power devices are discussed and simulated, including lateral IGBT, lateral MCT and double gate lateral MCTs. It is shown that lateral IGBT and lateral MCTs are good candidates for power IC applications.<br>Master of Science
2
Lovgren, Nicholas Keith. "Energy Harvesting From Exercise Machines: Forward Converters with a Central Inverter." DigitalCommons@CalPoly, 2011. https://digitalcommons.calpoly.edu/theses/520.
Full textAbstract:
This thesis presents an active clamp forward converter for use in the Energy Harvesting From Exercise Machines project. Ideally, this converter will find use as the centerpiece in a process that links elliptical trainers to the California grid. This active clamp forward converter boasts a 14V-60V input voltage range and 150W power rating, which closely match the output voltage and power levels from the elliptical trainer. The isolated topology outputs 51V, higher than previous, non-isolated attempts, which allows the elliptical trainers to interact with a central grid-tied inverter instead of many small ones. The final converter operated at greater than 86% efficiency over most of the elliptical trainer’s input range, and produced very little noise, making it a solid choice for this implementation.
3
Kaya, Ibrahim. "A Switch Mode Power Supply For Producing Half Wave Sine Output." Master's thesis, METU, 2008. http://etd.lib.metu.edu.tr/upload/12609781/index.pdf.
Full textAbstract:
In this thesis<br>analysis, design and implementation of a DC-DC converter with active clamp forward topology is presented. The main objective of this thesis is generating a rectified sinusoidal voltage at the output of the converter. This is accomplished by changing the reference signal of the converter. The converter output is applied to an inverter circuit in order to obtain sinusoidal waveform. The zero crossing points of the converter is detected and the inverter drive signals are generated in order to obtain sinusoidal waveform from the output of the converter. Next, the operation of the DC-DC converter and sinusoidal output inverter coupled performance is investigated with resistive and inductive loads to find out how the proposed topology performs. The design is implemented with an experimental set-up and steady state and dynamic performance of the designed power supply is tested. Finally an evaluation of how better performance can be obtained from this kind of arrangement to obtain a sinusoidal output inverted is thoroughly discussed
4
Mao, Shiwei. "Isolated Bi-directional DC-DC Converter with Smooth Start-up Transition." Thesis, Virginia Tech, 2015. http://hdl.handle.net/10919/52979.
Full textAbstract:
The bi-directional dc/dc converter is a very popular and effective tool for alternative energy applications. One way it can be utilized is to charge and discharge batteries used in residential solar energy systems. In the day, excess power from the PV panels is used to charge the batteries. During the night, the charged batteries will power the dc bus for loads in the house such as home appliances. The dual active bridge (DAB) converter is very useful because of its high power capability and efficiency. Its symmetry is effective in transferring power in both directions. However, the DAB converter has drawbacks in the start-up stage. These drawbacks in boost mode include high in-rush current during start-up, and the fact that the high side voltage cannot be lower than the low side voltage. A popular existing method to alleviate this problem is the use of an active clamp and a flyback transformer in the circuit topology to charge the high side before the converter is switched into normal boost operation. The active clamp not only helps eliminate the transient spike caused by the transformer leakage, but also continues to be used during steady state. However, this method introduces a new current spike occurring when the converter transitions from start-up mode to boost mode. To alleviate this new setback, an additional transitional stage is proposed to significantly reduce the current spike without the use of any additional components. The converter is current-fed on the low side, and voltage-fed on the high side. A simple phase shift control is used in buck mode and PWM control is used during the boost mode for both the start-up mode and the normal boost operation. This thesis discusses the performance results of a 48-400 V dc/dc converter with 1000 W power output.<br>Master of Science
5
Matejov, Michal. "Pasivní PFC filtry pro spínané napájecí zdroje." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2008. http://www.nusl.cz/ntk/nusl-217598.
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This work deals with theory of switched power sources. There is description of the ways for connection and their practice purposes. In the next parts there are defined requirements on input supply circuit for these sources, especially for the form of output current. There are mentioned the basic connecting methods of PFC circuits and these methods modify the output current to meet the requirements of specification ČSN EN 61000- 3- 2. In the next parts there are shown simulations of PFC circuits made by Pspice application. Further is the basic description of sources construction for the sources which were used for testing and measuring. The final part deals with evaluation of the measuring on the chosen computer’s source. It compares between the manufacturer’s solutions and PFC circuit made by ourselves.
6
Chin, Chun-liang, and 景淳良. "A Single-Stage Active-Clamp Forward Converter A Single-Stage Active-Clamp Forward Converter Employing Two Transformers." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/29523336939009639002.
Full textAbstract:
碩士<br>國立臺灣科技大學<br>電子工程系<br>102<br>This thesis presents a single-stage AC-to-DC power converter, which consists of a boost-type power factor corrector (PFC) and a two-transformer active-clamp forward converter. The PFC stage adopts the voltage-follower control under discontinuous conduction mode. It helps reduce the volume of the boost inductor. The current control loop is not required to reduce the circuit design complexity. By utilizing separate transformers, the proposed converter features zero-voltage switching and good line regulation over a wide range of the input voltage. The output power can be shared by two transformers to reduce their volumes and the stresses of components at secondary side. This allows high power density design.
The operating principle of this single-stage power converter has been analyzed, described and discussed in detail. The simulaton softwares, Mathcade and PSIM, are applied for circuit design. The experimental results with an input voltage of 115 Vac and an output of 19 V/140 W reveal a maximum efficiency of 85% and a maximum power factor of 0.99.
7
Chang, Yung-Chi, and 張詠冀. "Efficiency Improvement of Active Clamp Forward Converter." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/74700965120745504184.
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碩士<br>國立勤益科技大學<br>電子工程系<br>102<br>As the power transfer becomes more and more widely applied, the customers’ demands for the power efficiency, size and reliability becomes higher accordingly; however, the conventional forward diode rectifying converter can hardly meet the demands.
This paper adopts the active clamp structure to combine with auxiliary switches and clamper capacitance, which can effectively restrain the voltage transient and minimize the damages caused by switch changeover, as well as improve the converting efficiency. The capacity elements can operate a wider range of input voltage. In practice, the Pulse Width Modulation controller is used for the research on efficiency improvement of forward converter. From the experimental results, the methods proposed in the study have realized the improvement results.
8
Fan, Kuang-ming, and 范光銘. "Realization Study of an Active Clamp Forward Converter." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/92637859860667782736.
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碩士<br>國立臺灣科技大學<br>電子工程系<br>95<br>This thesis describes application of the active-clamp technique to achieve soft-switching for forward converters. For forward converters, the power switch causes high switching loss as the result of high current and high voltage generated during turn-on and turn-off periods. Generally, high switch loss hinders the improvement of efficiency and power density . In order to reduce switching loss, a resonant inductor is added in the primary side of the forward converter to form a resonant tank with the clamped capacitor. As the result, zero voltage switching (ZVS) for the main power switch can then be achieved to reduce the switching loss.
In this thesis, the state-space averaging technique is used to describe the state equation. K factor is applied to design compensator and to greatly enhance the stability of the system so as to meet the requirements. Finally, IsSpice is conducted to simulate the dynamics of the converter. Based on the simulated result, a 120W forward converter with voltage clamp is built to verify with the theoretical analysis.
9
Liu, Cheng-Chia, and 劉政佳. "Active-Clamp Forward Converter with Current Ripple Reduction." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/01282030322079346444.
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碩士<br>國立臺灣科技大學<br>電機工程系<br>97<br>A novel low input-current ripple topology named Active-Clamp Forward
Converter with Current Ripple Reduction (ACFRR) is proposed in this thesis. In
addition to having lower input current ripple and more than 50% duty cycle operation,
the fundamental component intensity of the ACFRR’s input current waveform can be
reduced by designing the circuit with its embedded filter.
To demonstrate ACFRR’s feasibility, the operational principle, simulation and
experimental results of the proposed converter operated at 150 kHz switching
frequency, 36-75V input and 5V/30A output are presented and its highest efficiency
is 84.88%.
Moreover, the conversion efficiency of the ACFRR can be further improved by
applying the synchronous rectification. According to the experimental results, the
highest efficiency, 86.69% of the synchronous rectification ACFRR is achieved.
10
Liao, Min-Chun, and 廖敏淳. "Comparison of Active Clamp Forward Converter and Asymmetrical Half-Bridge Converter." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/91272782578903555024.
Full textAbstract:
碩士<br>國立成功大學<br>電機工程學系碩博士班<br>93<br>This thesis mainly studies and implements two two-stage AC/DC power converters. The front-stage is a power factor correction circuit and the second-stage is a soft-switching DC/DC converter with synchronous rectifier. The DC/DC converter applies active clamp forward converter and asymmetrical half-bridge converter individually. These two circuits have similar zero-voltage-switching operating features, and the main circuit has the same number of components. A comparison between the two topologies is made in this thesis. The power consumption at no load condition can be reduced by disabling the power factor correction circuit and synchronous rectifier. In addition, the pulse skip scheme is used to reduce the losses of the converter at no load condition. Experimental results show that both these two prototypes can achieve 87% efficiency and 0.95 power factor at DC 12V/8A output condition.
11
Chang, Din-Uan, and 張丁元. "Research and Implementation of An Active Clamp Forward Converter." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/45609318839380239285.
Full textAbstract:
碩士<br>國立高雄應用科技大學<br>電機工程系碩士班<br>95<br>This thesis introduces the circuit behavior of an active clamp forward converter and the range of dead time between two switches. Since there are the dc bias current problem and core saturation problem in the main transformer, we will consider these problems in the design process of resonant inductor. An active clamp forward converter uses two power MOS-FETs, an additional inductance and a clamp capacitance to recycle the energy of leaking inductance to achieve ZVS. Since we utilize the active clamp circuit to reset magnetic energy, the reset winding became unnecessary and duty cycle can be greater than 0.5.This work not only describes the system circuit behavior on every time stage but also verifies the theory by Pspice and Matlab software. Finally, an prototype active clamp forward converter is built to verify the zero switching and the suitable design of resonant inductor.
12
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<br>國立臺灣科技大學<br>電子工程系<br>87<br>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
13
Liu, Ya-Jhe, and 劉亞哲. "Study and Implementation of a Novel Active Clamp Forward Converter." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/3gax6f.
Full textAbstract:
碩士<br>國立臺灣科技大學<br>電子工程系<br>102<br>This thesis presents the study and implementation of a novel active clamp forward converter to solve the voltage spike problem on the freewheel diode at secondary side. The voltage stress and the switching loss of the secondary component can thus be reduced. At the same time, the primary-side switch can be turned off at decreased drain current to lower the switching loss. Moreover, by adopting the active clamp circuit, the primary-side switch can achieve zero-voltage turn-on to reduce the switching loss and raise the conversion efficiency. The operating principles are analyzed in detail. Finally, a 480-W prototype of the proposed active clamp forward converter has been built according to the design procedures. The peak efficiency can be up to 94.88%.
14
Pai-HsiangKuo and 郭百祥. "A High Step-Up Forward/Flyback Converter with Active-Clamp." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/33641879666943672421.
Full textAbstract:
碩士<br>國立成功大學<br>電機工程學系碩博士班<br>98<br>In this thesis, a high step-up forward/flyback converter with active-clamp circuit is proposed. The circuit topology of the proposed converter consists of a transformer, switch, resonant capacitor, an active-clamp circuit, and the output voltage doubler circuit. By utilizing the transformer and output voltage doubler, the proposed converter can achieve high voltage gain. The proposed converter functions as the forward and flyback integrated converter. In additional the active-clamp circuit is employed to recycle the leakage-inductance energy of the transformer and thus the stresses on the switches are reduced and zero-voltage-switching (ZVS) are achieved. Thus, the system efficiency can be improved. Finally, a prototype circuit with 24-V input voltage, 200-V/ 400-W output power is implemented to verify the performance.
15
Syu, Sheng-Yao, and 徐聖堯. "A Study of Active-Clamp Forward Converter with Synchronous Rectification." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/72636783402056592877.
Full textAbstract:
碩士<br>國立臺灣海洋大學<br>電機工程學系<br>97<br>The circuit analysis of high-side and low-side active-clamp forward converters with synchronous rectification (HACFC-SR/LACFC-SR) are presented in this thesis.
The converters are composed by a conventional forward converter and an additional clamp circuit which is formed with an auxiliary switch and a clamp capacitor. With the help of clamp circuit, the flux in the transformer can be reset without tertiary winding in the converters. Moreover, the advantages of active clamp technique are including：lower voltage stress on the main power switch, the ability to switch at zero voltage, reduced EMI and duty cycle operation above 50%. Furthermore, the synchronous rectification (SR) is used to reduce conduction losses for the low voltage/high current application.
Finally, to analysis the steady-state to the converter, the theoretical result of thesis is proved by simulation, to verify theoretical analysis and feasibility of technique.
16
Wu, Chao-Han, and 吳昭漢. "Stability Study of Active-Clamp Forward Converters." Thesis, 2004. http://ndltd.ncl.edu.tw/handle/17371339052081961784.
Full textAbstract:
碩士<br>義守大學<br>電機工程學系<br>92<br>In order to improve the efficiency of the isolated switched mode power supplies, an active-clamp circuit is usually used at the primary side of the transformer to reset the transformer, to suppress the turn-off surge and to achieve the energy recovery of the surge.
Some previous works regarding the effect of the active-clamp circuit on flyback converter have been reported. The converter that has an unstable phenomenon for a certain range of clamp capacitance is addressed through analytical and experimental considerations. Using the active-clamp circuit to suppress the turn-off surge will become more popular since the voltage rating of the primary switch in a forward converter is usually higher than that of other converters. The paper is to clarify the effect of clamp capacitance on an active-clamp forward converter by both the experiment and the analysis.
17
Lin, Yang-Cheng, and 林揚城. "Study of Forward Converter with Uninterrupted Characteristic and Active-Clamp Technology." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/79617431053556849342.
Full textAbstract:
碩士<br>國立臺灣海洋大學<br>電機工程學系<br>96<br>Abstract
The purpose of this thesis is based on the circuit structure of off-line forward converter, And utilize the auxiliary winding to achieve power factor correction and battery charging. In accordance with forward converter structure add Active-Clamp technology to reach control voltage surge and transformer reset function. Leakage consumption energy will go up again to the host circuit, to enable the entirety energy exploitation be forever, let an user extend much time.
This thesis will coordinate the textbook theory and match the inferential reasoning formula as well as the IsSpice computer simulation. Finally we confirms this electric circuit usability .
18
HSIAU, JIA-BIN, and 蕭家斌. "Study and Implementation of a Two-Transformer Active-Clamp Forward Converter." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/vx6mb5.
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碩士<br>國立臺灣科技大學<br>電子工程系<br>99<br>This thesis aims to study a two-transformer active-clamping zero-voltage-switching (ZVS) forward converter for low-profile power supply applications. The proposed topology is mainly composed of two active-clamping counterparts with two separated transformers. Only two switches are required. The proposed converter has the advantages of high efficiency, simple circuit and low cost. The operating principles and design considerations of the proposed converter are analyzed and discussed in details. A laboratory prototype is built and tested to verify the feasibility of the proposed scheme. The experimental results are satisfactory.
19
Chen, Chun-Yu, and 陳俊佑. "UPS Forward Converter with Active-Clamp Technology and Power Factor Correction." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/22064632138434548595.
Full textAbstract:
碩士<br>國立臺灣海洋大學<br>電機工程學系<br>103<br>The research purpose of this thesis is based on the circuit structure of UPS forward converter, increasing the power factor correction function on the forward converter; the resulting output efficiency can be further enhanced. And utilize the auxiliary winding to attain battery charging.
Added active-clamp technology for the forward converter architecture could achieve the functions of resets the transformer and voltage surge suppression, the energy consumed by the magnetic flux leakage feeds back to the main line, with the power factor correction circuit so that the overall energy efficiency can be effectively improved, thus increasing the using time.
This article combines derivation and the IsSpice application software to simulate, which confirms the feasibility and practicality of this circuit.
20
Hang, Yen-Cheng, and 黃彥琛. "Analysis and Implementation of Boost type Active clamp ZVS forward converter." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/23528365974851532557.
Full textAbstract:
碩士<br>國立雲林科技大學<br>電機工程系碩士班<br>95<br>This thesis discusses the analyzing and implementation of the boost type active clamp forward converter with two transformers. On circuit frame, the technique is link up boost type active clamp technology and forward converter with high switching frequency (fs=150kHz) and high efficiency (n=85%).
In addition, the active clamp circuit frame can also help the main switch to turn on at zero voltage switching. Moreover, the auxiliary switch is also operated at ZVS. An auxiliary switch and a clamp capacity on is used in the forward converter to recycle the energy stored in the transformer leakage in order to minimize the spike voltage at the transformer primary side. Therefore the voltage stress of man switch can be reduced.
Finally, a 180W (12V/15A) forward converter has been implemented to verify the effectiveness of the active clamp forward converters.
21
LIN, CHING-JU, and 林靜如. "Characteristic Analysis and Realization Study of Active Clamp Circuit for Forward Converter." Thesis, 2001. http://ndltd.ncl.edu.tw/handle/31057162250611793119.
Full textAbstract:
碩士<br>國立臺灣科技大學<br>電子工程系<br>89<br>This thesis is to investigate the characteristic of the active-clamp topology for the forward converter. A resonant inductor is included in the primary-side of the transformer for achieving a resonant tank with the clamped capacitor. The inductor current and capacitor voltage characterized for building zero-voltage-switching in main switch during each switching cycle. A state-space averaging technique is used to describe the state equation. The compensation is implemented by K-factor technique. The Bode diagram of open-loop and closed-loop system are conducted to verify the system stability. The dynamic performance of the proposed converter is simulated by IsSpice. According to the estimated characteristic, a design procedure is proposed. A design example is implemented to verify the simulation and the theoretical.
22
Chen, Ke-Cheng, and 陳科澂. "Design and Implementation of a Digital-Controlled and Active-Clamp Forward Converter." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/9dcpr3.
Full textAbstract:
碩士<br>國立臺北科技大學<br>電機工程系電力電子產業碩士專班<br>106<br>The purpose of this thesis is to design and implement a digital-controlled and active-clamp forward converter. Based on the design of active-clamp architecture, a clamp capacitor and a resonant inductor are used to recover the energy from transformer leakage inductance to improve shortcomings such as high switch stress and RCD snubber power loss in the traditional forward converter. All switches have zero voltage switching (ZVS) characteristics in the implemented active-clamp forward converter to reduce the switching loss. In the utilized forward converter, two switch control signals, both are complementary of which property is different from the traditional interleaved forward converter having 180˚phase-shifted switch control signal. Therefore, the two output inductor currents are interleaved and the output current ripple can be reduced.
The implemented forward converter specifies the maximum power 240W, the input voltage 380V, the output voltage 24V and the operation frequency 100kHz. The used controller is the microcontroller TMS320F28035 produced by Texas Instruments. It is verified that the efficiency reaches more than 93% at full load as well as the analysis on operation waveform and overall circuit loss can be proved with the simulation software PSIM.
23
Liao, Li-Yuan, and 廖俐媛. "Study and Implementation of a Dual-Resonant Active-Clamp Forward/Flyback Converter." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/00245536160598209610.
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碩士<br>國立臺灣科技大學<br>電子工程系<br>103<br>This thesis aims to study and implement an isolated high step-up converter that improves the efficiency and durability that plagues the conventional DC-DC converters for renewable energy sources. Generally, the input, such as photovoltaic arrays and the fuel cell stacks, of the above mentioned converters are generally of low voltages. Thus, a high voltage step-up converter is required to boost the voltage a higher voltage level for the front-end applications. However, the efficiency and voltage gain of conventional DC-DC step-up converters are limited due to the parasitic components. Furthermore, galvanic isolation is a common requirement for such converters, further degrading the efficiency due to the added transformer. In order to solve the above mentioned problems, this thesis proposes a dual-resonant active-clamp forward/flyback converter. This topology is a combination of forward converter and flyback converter, while increasing the utilization of transformer. Moreover, by utilizing the additional inductor to introduce resonance into the circuit, the zero-voltage-switching (ZVS) region of the switches is increased and zero-current-switching (ZCS) turn-off for diodes is achieved. Meanwhile, fixed frequency pulse width modulation (PWM) can be maintained by simply selecting the correct component parameters in the resonant tank. Moreover, the proposed converter has low voltage ripple owing to the parallel connection of two resonant output rectifiers in secondary, facilitating the elimination of electrolytic-capacitors. This thesis first proceeds with the circuit analysis of this proposed topology, then discusses the design considerations. After that, simulation is done with Powersim. Finally, a 250W prototype circuit is implemented to verify the theoretical examination.
24
Wu, Chung-Liang, and 武仲良. "Robust Design of Two AC/DC Switching Mode Power Supplies: Two Switch Forward Converter and Active Clamp Forward Converter." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/44480149897340829563.
Full textAbstract:
碩士<br>國立高雄第一科技大學<br>機械與自動化工程所<br>94<br>Abstract
The aim of this thesis is to implement the Toguchi concept of robust design by
running a partial factorial set of experiments using orthogonal arrays. The AC to
DC switching mode power supplies (two switch forward converter and active
clamp forward converter) arm at achieving the separability of electronic
elements into control factors and elements’ specification into level, and take
exalt the output efficiency as quality goal, consideration in input terminal to
supply AC voltage (noise factor) variables, and to determine optimum
collocation for factor levels. Analyzes using experimental result to determine
optimum collocation for factor levels and analysis of variance (ANOVA) can be
used to identify the factors with the highest effect and percentage contributions,
it can be allowed the designer to depend on the factor to quality goal
iii
contribution, to choose the low cost circuit elements specification and reduce the
manufacture cost. It also used the least number of experimental to obtain an
optimum collocation for factor levels, to reduce the experimental cost and
improve the defect of conventional techniques by using try and error method.
The optimization efficiency for two switch forward converter as follows:
115Vac, 85.49% and 220Vac, 88.62%, the optimization efficiency for active
clamp forward converter as follows: 115Vac, 87.56% and 220Vac, 90.87%.
Consequently, it is illustrated application of Toguchi method to robust design
and effectively to improve output efficiency and quality performance of power
supply.
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Kao, Yu-Hsiang, and 高裕翔. "The Development of High Power Factor Active Clamp Zero Voltage Switching Forward Converter." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/90714844100072352299.
Full textAbstract:
碩士<br>國立東華大學<br>電機工程學系<br>95<br>The subject of this thesis is to analyze and design a high power factor active clamp zero voltage switching forward converter. The active clamp zero voltage switching forward converter with power factor corrector allows zero voltage switching (ZVS) while retaining the merits of simple circuit designed and low stresses. The active clamp ZVS forward converter uses parasitic components to resonate. Therefore, additional resonant components are not required. Moreover, the switching stresses are reduced by using of ZVS resonant technique.
The high power factor active clamp ZVS forward converter has the merit of fixed duty cycle operation. A combination of parasitic components, which includes the MOSFETs output capacitance and the leakage inductance of the isolation transformer, produces a resonant action and reduces drain-source voltage prior to turn-on. Moreover, the switching loss is reduced relatively. Therefore, high efficiency operation of system is achieved. The NCP1280 IC manufactured by ON Semiconductor Corp. is adopted in this thesis as the pulse width modulation (PWM) controller. The unique active clamp topology can recycle energy of released magnetic force, and simplifies the driving circuit of the MOSFETs. Finally, the experimental results of the power factor corrector, ZVS and efficiency have shown the effectiveness of the designed active clamp ZVS forward converter with power factor corrector.
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Chung-WenLiu and 劉忠文. "Design and Implementation of an Active-Clamp Forward Converter with GaN Power Device." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/84vg9s.
Full text
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Jin, Cai-Xin, and 蔡欣錦. "Implementation of a single-phase inverter based on a Active-clamp forward converter." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/80767533894160327320.
Full textAbstract:
碩士<br>東南科技大學<br>電機工程研究所<br>98<br>This thesis proposes a novel single phase inverter based on the active clamp forward converter technique. First, an active clamp forward converter is used to boost the DC input voltage and to output a sinusoidal full-wave rectifier type voltage. Then the full bridge switches circuit of the inverter changes the polar of the output voltage by controlling the states of the switches to output an AC sinusoidal voltage. The active clamp forward converter has the advantages of simple structure, small size, and low switching los. Moreover, because the switches of the full bridge circuit are used to change the polar of the output voltage, the switching frequency and switching loss are low, so that the output efficiency of the inverter is high. Next, the exactitude of the control circuits was validated by using the simulation. Moreover, an active clamp forward inverter is actually implemented. A Texas Instruments digital signal processor, TMS320F2808, is used to execute the control scheme and control the driving signal. As a result, a fully digital control system is realized to reduce the hardware circuits. Finally, the experimental results can validate the exactitude and the practicability of proposed circuit.
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Shih, Chieh-Lung, and 施傑瀧. "A Current-Doubler Rectifier Two-Switch Active-Clamp Forward Converter with One Ground-Clamp Diode: Analysis and Implementation." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/94583761255953538434.
Full textAbstract:
碩士<br>崑山科技大學<br>電機工程研究所<br>101<br>A current-doubler rectifier two-switch active-clamp forward converter with one ground-clamp diode is proposed in this thesis. The proposed exhibits the features of wide-input voltage-range application, low output current ripple and high efficiency. A two-switch active-clamp forward converter has a main drawback that its maximum duty ratio is limited to 0.5 to guarantee flux reset for the magnetizing inductor of transformer. The limitation of duty ratio causes the narrow input voltage range. In order to overcome this drawback, the hybrid-bridge switching circuit structure of a two-switch active-clamp forward converter should be destruct. Therefore, two switches and only one ground-clamp diode are utilized to the proposed converter herein. Moreover, a delay turn-off gate signal is used to drive the grounded switch, and thus all the switches of the proposed converter can achieve zero-voltage switching (ZVS) condition under turn-on transition. On the other hand, when the proposed converter with current-doubler rectifier can be operated at duty ratio , it can provide the output current ripple cancellation completely to reduce the size of output filter and increase the power density.
The operating principles, component design and power switch selection of the proposed converter are investigated. The IsSpice simulations and experimental results are provided based on an input voltage 400 V, output voltage 48 V and output power 200 W prototype to verify the theoretical analysis of the proposed converter. In addition, according to the experimental results, the maximum power efficiency of the proposed converter is about 84%.
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Hsu, Yen-Hui, and 許燕輝. "A Study in the Efficiency Improvement of Active Clamp Forward Converter with Synchronous Rectification." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/81968749073025272556.
Full textAbstract:
碩士<br>國立高雄應用科技大學<br>電機工程系<br>98<br>In this thesis, an active clamp forward converter architecture with synchronous rectification is used for the development of DC-DC converter with high efficiency. First, the operation principle of active clamp forward converter is introduced, and a converter prototype is designed in accordance with a certain specifications. Second, the working waveforms are simulated by the software SIMetrix, and the efficiency of the converter operating in zero-voltage switching mode and low-voltage mode is compared. Finally, Taguchi method is employed to find control factors affecting conversion efficiency, and the orthogonal array experiments is carried out to find a combination of optimal parameters. The simulation and experiment results illustrate that Taguchi method can be effectively used to improve conversion efficiency of a DC-DC converter with synchronous rectification, and the feasibility of the prototype converter is also validated.
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Jheng, Geng-Ting, and 鄭亙廷. "Analysis and Implementation of An Active-Clamp Forward Converter with Center-Tapped Synchronous Rectifiers." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/8k7ne5.
Full textAbstract:
碩士<br>崑山科技大學<br>電機工程研究所<br>96<br>The analysis, simulation, modeling and implementation of an active-clamp forward converter with center-tapped synchronous rectifiers(ACFC-CTSR) are presented in this thesis.
The converter uses the active-clamp circuit to replace the tertiary winding for flux resetting. It can improve the duty ratio limitation. The main and auxiliary switches can achieve zero-voltage-switching(ZVS) to reduce the switching loss with proper components design of the resonant circuit. Furthermore, the synchronous rectification is used in the secondary side to reduce the conduction loss of rectifier diodes in high output current applications.
The circuit of the ACFC-CTSR converter is analyzed in detail and the IsSpice simulation is applied to verify the accuracy of theoretical analysis. The small signal model is derived by the state-space averaging method and verified by the frequency response measurement of the dynamic signal analyzer(Aglient 35670A). A controller is designed to eliminate the effects of input voltage and load variations on the output voltage.
Finally, experimental results are presented of a 100 W prototype converter with an input voltage 30 ~66 V, an output voltage of 5 V/20 A, and operating of a switching frequency of 100 kHz. The maximal efficiency is 91.9 %. In general, good agreement is observed between the theoretical and experimental results.
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Sheng, Ying-Jin, and 盛瀅瑾. "Study and Implementation of an Active-Clamp Forward Converter with Non-linear Conversion Ratio." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/66ds57.
Full textAbstract:
碩士<br>國立臺灣科技大學<br>電子工程系<br>102<br>This thesis presents the study and implementation of an active-clamp forward converter with non-linear conversion ratio. In general, an active-clamp forward converter operating at a smaller duty cycle will lead to lower conversion efficiency. Therefore, this condition is usually avoided in the design stage. By changing the circuit architecture of the secondary side, the presented converter is more suitable for wide input voltage range and high step-down ratio applications. Furthermore, the zero-voltage-switching (ZVS) feature for the main switch and auxiliary switch can be achieved by the active-clamp circuit to reduce the switching losses. The operating principles and design considerations of the proposed converter are analyzed and discussed in detail. A prototype circuit of an active-clamp forward converter with non-linear conversion ratio has been implemented. The input voltage is 400 V, the output voltage is 12 V, and the output current is 20 A. Theoretical analyses are verified with the experimental results.
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Kora, BharathKumar, and Bharath. "Analysis and Design of Active Clamp Forward/Flyback DC-DC Converter for Micro Inverters." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/22550850209154283431.
Full textAbstract:
碩士<br>國立臺灣科技大學<br>電子工程系<br>102<br>The thesis presents an isolated high step-up forward/flyback active-clamp
converter with output voltage lift. In order to obtain high step-up voltage gain, the
output voltage lift is adopted. The characteristics of the output voltage lift are similar
to the forward converter operates charging mode. The flyback converter operates
discharging mode.The active-clamp circuit is employed to recycle the
leakage-inductance energy of the forward/flyback transformer and to suppress the
voltage stress on the switch. By utilizing the active-clamp circuit, both primary and
auxiliary switches can achieve zero voltage- switching (ZVS), thus improving the
efficiency of the proposed converter. Lossless switching of the main switch
independent of the line and load conditions no increase in conduction losses, simple
power and control circuitry, and capability of operating in either voltage or current
mode control.
The converter operates at boundary mode between current continuous and
discontinuous mode to achieve ZVS. Variable frequency with fixed off time is used for
reducing core losses of the transformer, achieving high efficiency. Meanwhile, power
distribution between forward and flyback is analyzed as well. Finally, a prototype
circuit with 24-V input voltage, 400-V output voltage, and 150-W output power is
implemented to verify the performance.
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Cheng, Hsin-Wei, and 鄭欣煒. "Application and study of high frequency magnetic components for an active-clamp forward converter." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/92435979499240155048.
Full textAbstract:
碩士<br>國立中正大學<br>電機工程所<br>97<br>This thesis presents application and study of high frequency magnetic components for an active-clamp forward converter with synchronous rectifier. Recently, the usage of planar transformers and inductors has gradually increased. Due to high efficiency, low leakage inductance, low volume size and wide operating frequency, planar transformers have gradually substituted for conventional ones. In the thesis, first, analysis and design consideration of the topology of an active-clamp forward converter with synchronous rectifier are presented. Then, the performance and comparison of measurements of the circuit operated at the frequencies of 250 kHz and 500 kHz are discussed. Finally, the transformers with different types of material, such as 3C96 manufactured by Ferroxcube and MZ49 and MF91 by Himag Magnetic Corporation are used in the design, from which experimental measurements have verified its feasibility.
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Liu, Yu-Chen, and 劉宇宸. "Analysis and Implementation of an Active Clamp Forward Converter with an Improved ZVS Auxiliary Circuit." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/27790337449268469604.
Full textAbstract:
碩士<br>崑山科技大學<br>電機工程研究所<br>99<br>In order to achieve zero voltage switching (ZVS) for the both primary switching and auxiliary switch in the active clamp forward converter, an improved active clamp ZVS forward converter is presented and analyzed in detail in this thesis.
The converter is composed of a conventional ZVS forward converter and an auxiliary network which consists of a clamp capacitor and an inductor. With the help of auxiliary network, the switches could easily achieve ZVS and reduce the switching losses in wide-load range. Furthermore, the synchronous rectification (SR) is used at low side to reduce the conduction losses. In addition to the circuit analysis, the IsSpice simulation is also applied to verify the accuracy of theoretical analysis.
Finally, the prototypes of an active clamp forward converter with an input of 48 V, on output of 5 V/ 3.5 A, and the switching frequency of 200 kHz has been implemented in the laboratory. In general, good agreement is observed between the theoretical and experimental results.
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Wang, Min-Ji, and 王敏吉. "Design and Large-Signal Analysis of the Active-Clamp Reset Forward DC/DC Converter Modules." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/76479144327925986704.
Full textAbstract:
碩士<br>國立雲林科技大學<br>電機工程系碩士班<br>94<br>The modern power products towards the development of low-voltage, large current, small profile, low cost and high-efficiency. Among them, the forward converter is a proper design structure. By raising the switching frequency to 350KHz, the most volume and weight of the transformer and inductance can be reduced. The wire windings of the transformer and inductance can be layout on the PCB board to replace the traditional wire windings on the bobbin and make this structure have the advantage of the small profile. However, when the switching frequency is raised, the switching losses and electromagnetic interference will increase, so how to reduce the losses and interference and increase efficiency is worth research and discussion in the process of designing and developing the products. Therefore, this thesis adopts the technique of active-clamp reset in order to improve the efficiency of the whole system. The relevant design, analysis, proof, simulation and experiment have already been finished in this thesis.
Besides, this thesis analyzes the large-signal transient for two kinds of the active-clamp reset forward converter. During the line and load transient changes of the converter, the maximum magnetizing current of the transformer, the peak voltage of the main switch and the overshoot of output voltage will affect the dynamic performance and safety range in the operation of circuit. The state trajectory and average state trajectory approaches are used to analyze their transient behavior about the maximum magnetizing current of the transformer and the peak voltage of the main switch in order to under the worst-case conditions its parameter situation of change can be estimated and examined in advance, and can observe the dynamic response of the circuit to enable the whole system designed in the safe requirement in advance.
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Yen-HungKo and 柯延鴻. "Study and Implementation of High Step-down DC-DC Forward Converter with Active Clamp Circuits." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/53099058501337438333.
Full textAbstract:
碩士<br>國立成功大學<br>電機工程學系<br>102<br>In this thesis, a high step-down DC-DC forward converter with active clamp circuits is proposed. By integrating two active clamp circuits into the proposed converter, the high step-down capability and soft-switching feature can be achieved without using extreme duty cycle of the active switch so that the conversion efficiency of the proposed converter can be further enhanced. In this thesis, the operation principle of the proposed converter is first addressed. Then, the steady-state analysis is presented. According to the derived equations of the steady-state analysis, one can further design the circuit parameters in hardware implementation. Finally, a laboratory prototype with 400V input voltage, 24V output voltage, and 200W output power rating is implemented to verify the validity of the proposed converter. The experimental results of the constructed converter prototype show that the highest of 95.25% can be achieved at the 80W output load condition.
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ChangHuang-chang and 張煌章. "Analysis and Implementation of Active-Clamp Forward Converters with Synchronous Rectification." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/46798995818384891661.
Full textAbstract:
碩士<br>崑山科技大學<br>電機工程研究所<br>95<br>The circuit analysis, components design and system implementation of high-side and low-side active-clamp forward converters with synchronous rectification (HACFC-SR/LACFC-SR) are presented in this thesis.
The converters are composed by a conventional forward converter and an additional clamp circuit which is formed with an auxiliary switch and a clamp capacitor. With the help of clamp circuit, the flux in the transformer can be reset without tertiary winding in the converters. Moreover, the clamp circuit not only mends spike voltage produced by leakage inductor energy but also offers the main and auxiliary switches to achieve zero-voltage switching (ZVS) that reduces switching losses. Furthermore, the synchronous rectification (SR) is used to reduce conduction losses for the low voltage/high current application. After the circuit analysis, the IsSpice simulation is applied to verify the accuracy of theoretical analysis and experiment.
The converters transfer functions are derived by the state-space averaging approach. The analysis result is verified by the practical measurement of the dynamic signal analyzer Agilent 35670A. A controller is then designed to eliminate the effects of input voltage and load variations on the output voltage.
Finally, the prototypes of HACFC-SR and LACFC-SR with 30~60 V input and 5V/ 20A output have been implemented in the laboratory. The experiment results show that all switches can achieve ZVS operation, the highest power efficiency 93.36%, and the output voltage is well regulated under input voltage and load variations.
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Shih, Kun-liang, and 施坤良. "Analysis and Implementation of the Active Clamp Interleaved Bi-Forward Converters." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/24657601711348687194.
Full textAbstract:
碩士<br>雲林科技大學<br>電機工程系碩士班<br>97<br>The thesis presents the interleaved bi-forward converter with active-clamp technique,which mainly composes of two forward converters in order to reduces cost and complexity of the circuit. The active-clamp technique not only resets the energy stored in transformer and clamps voltage stresses of switches, but also achieves the zero-voltage switching to reduce the switching losses and the voltage spike on switches. The PWM signals of main switch and auxiliary switch are complementary to each other, the duty cycles are not limited within 50%. In output side, the interleaved technique is used to raise the output power, share the load current and reduce the output current ripple. Finally, simulations and experimental results are given based on an input 200V, output 48V, 650W prototype to verify the feasibility of the proposed converter.
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Li, Ming-Ying, and 李明穎. "Analysis and Implementation of the Active Clamp Two-Switch Forward Converters." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/03861473675181932759.
Full textAbstract:
碩士<br>雲林科技大學<br>電機工程系碩士班<br>96<br>The thesis presents an active-clamp two-switch forward converter. The active-clamp technique clamps the voltage stress of switch, and it also achieves the zero-voltage switching which reduces the switching loss and the spike on switch. Furthermore, it improves the efficiency of the converter. At the secondary of the transformer, the current-doubler rectifier is used instead of the half-wave rectifier to reduce the root mean square current of the secondary-winding. Also, two output filter inductors cancel the current ripple so as to eliminate the voltage ripple on the output capacitor. Finally, according to the operation principle, the steady-state analysis and the component design presented in the thesis, a 400V input, 12V output with 360W prototype is made, and the experimental result of related waveforms is shown to prove the feasibility of the configuration.
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Lin, Chung-yi, and 林宗億. "Study and Implementation of an Active-Clamp Forward Converter with Synchronous Rectification and Non-linear Conversion Ratio." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/88616602982218299533.
Full textAbstract:
碩士<br>國立臺灣科技大學<br>電子工程系<br>103<br>This thesis aims to study and implement an active-clamp forward converter with synchronous rectification and non-linear conversion ratio. The circuit topology is an active-clamp forward zero-voltage-switching converter with an additional non-linear gain cell that consists of inductors and synchronous switches. A wide input-voltage range and a high step-down ratio can be achieved by the studied converter circuit. The main and auxiliary switches can be operated under zero-voltage switching to reduce switching losses and improve the conversion efficiency. A laboratory prototype for the studied active-clamp forward converter with non-linear conversion ratio was implemented and tested under 150 V input voltage and 12 V/ 54 A output conditions. The experimental results are shown to verify the theoretical analysis.
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Liu, Chih-Wen, and 劉誌文. "The Design and Implementation of a Two-Quadrant Active Clamp Forward Converter with Power-Factor-Correction Converter with Power-Factor-Correction." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/98688362522878433226.
Full textAbstract:
碩士<br>國立高雄應用科技大學<br>電機工程系<br>97<br>This thesis focuses on the analysis and design of a two-quadrant active clamp forward converter with active power factor correction. First, the characteristics of the power factor correction and conventional active clamp forward converter will be analyzed in this thesis, and then an improved two-quadrant active clamp forward converter topology is proposed. The topology will focus on solving the problems that when the main power switch of conventional active clamp forward converter is turned off, it will need to afford higher voltage stress, and that the zero voltage switching conditions between the main switch and auxiliary switch has big difference. Finally, the theory is verified by IsSpice software and a 100W AC-DC power converter is implemented. The maximum efficiency of the two-stage converter is 83%.
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Deng, Bo-Cheng, and 鄧博誠. "Analysis and Design of A Novel ZVS Single-Stage Active Clamp Forward AC/DC Converter with High Power Factor Correction." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/89555846495651503660.
Full textAbstract:
碩士<br>國立成功大學<br>工程科學系碩博士班<br>96<br>Due to the quality of the power converter depends on the power factor and the conversion efficiency, a novel zero-voltage-switching (ZVS) single-stage active clamp forward AC/DC converter is proposed in this paper. It is verified to exhibit with both high power factor and high conversion efficiency.
The proposed converter is an integration of buck-boost and active clamp forward converter by means of the component placement. Thanks to the inherent high power factor of buck-boost converter and the soft-switching property of active clamp forward converter, the current-feedback controller and soft-switching auxiliary circuit are not necessary to achieve high power factor and ZVS. Hence, the cost of the converter is substantially reduced. In addition, since the energy stored in the transformer leakage inductance is recycling and the transformer is operating in the multi-quadrant of the B-H plane, the voltage spike at the switch can be suppressed and the size of the transformer can be thereby minimized.
In this thesis, the operating principle and the averaged mathematical model of the novel converter are presented. Then, the value of each component is well designed to satisfy the electrical specifications and ZVS operation conditions. After determining the value of each component, the graphical method proposed by Professor Lin is adopted to derive the small-signal model of the novel converter. The voltage-feedback controller can then be designed by applying the classical control theory. Finally, the theoretical analysis is verified by IsSpice simulations and the experimental results.
The experimental results reveal that when the input voltage , the switching frequency , the output voltage and the output power , the proposed converter exhibits power factor of 0.986 and efficiency of 86 % at full load. It validates the properties of high power factor and high conversion efficiency of the proposed converter.
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Yu, Zih-Min, and 虞子旻. "Optimization of Experiments and Development on the Active-Clamp Forward Converters with Synchronous Rectification for the Ocean Current Power Generation System." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/99920914467791381286.
Full textAbstract:
碩士<br>國立高雄第一科技大學<br>系統資訊與控制研究所<br>98<br>This thesis aims at the investigation on implement of the power converter for ocean current generation system. In this system, a prime mover is used to drive the water flowing within a constructed water tank so as to simulate the behavior of ocean current. The flowing water can further drive a permanent synchronous generator for generating power. When the generator is operated, the characteristics of the generator will be further obtained. A converter can be designed in accordance with the characteristics. In this thesis, an active-clamp forward converter with synchronous rectification is employed to convert and delivery power produced by the ocean current energy. Meanwhile, a synchronous rectification technique is integrated in the forward converter for reducing the power loss of the power switches. Furthermore, the Petri net is used for analysis of the diving signal of the resonant converter. Besides, a bidirectional power converter is further provided in the load stage of the forward converter. Accordingly, the power can be controlled to flow from power grid to battery or from battery to load.
Moreover, in this thesis, Taguchi method and dual response surface method are used to evaluate the optimal output power efficiency of the resonant converter. Importantly, the Fuzzy-based Taguchi Method is also utilized to analysis the preferred combination for two quality characteristics including power and efficiency of the forward converter such that the performance of the proposed ocean current generation system can be further optimized.
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Yu, Fu-Kung, and 余富恭. "Implementation of an Active Clamp Flyback Converter." Thesis, 2004. http://ndltd.ncl.edu.tw/handle/18992585177428643031.
Full textAbstract:
碩士<br>國立雲林科技大學<br>電機工程系碩士班<br>92<br>The high voltage stress of power semiconductors caused by the parasitic element of the transformer and the power switch in high frequency switching mode power supply when power switch is turn off . RCD clamped circuit is used to limit the switch voltage surge. However, the energy stored in the transformer leakage inductance will be dissipated in the clamp resister. It will reduce the efficiency of converter. In this paper an active clamp circuit technology is used to reduce the peak voltage stress across the power switch. The transformer leakage inductance and the equivalent capacitor including the clamp capacitor and the parasitic element across power switch are used to achieve the Zero Voltage Switching for power switch. The active clamp scheme can reduce switching loss at power switch, reduce EMI, and increase power converter efficiency.
The operation principle of active clamped flyback converter is presented. The experimental results are discussed is this paper.
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Que, Bai-song, and 闕百淞. "Active-Clamp Flyback Converter with Synchronous Rectification." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/79054355945786810516.
Full textAbstract:
碩士<br>國立臺灣科技大學<br>電子工程系<br>101<br>This thesis focuses on the study and implementation of an active-clamp flyback converter, and compare it to a conventional flyback converter. The active-clamp flyback converter uses a capacitor to absorb the leakage inductor energy of the transformer and eliminate the voltage spike when the switch is turned off. Also the zero-voltage switching is achieved by the resonant tank to raise the conversion efficiency. The discussed active-clamp flyback converter is operated under CCM at light load. Therefore, the synchronous rectification is easier to fulfill. The operating principles are discussed. A prototype converter with an input AC voltage range from 90 Vac to 264 Vac and an output of 19 V/45 W is implemented and tested. The efficiency at rated load is 89.5%.
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Liu, Yu-Sheng, and 劉育昇. "Design and Implementation of Active Clamp Forward Inverter." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/48058302709863460831.
Full textAbstract:
碩士<br>清雲科技大學<br>電機工程所<br>100<br>The aim of this thesis is to develop a small scale DC-AC inverter based on active clamp forward topology for either stand-alone or grid-connected applications. The proposed inverter is characterized by a single stage structure in which active clamp forward conversion is adopted on the DC side and a full bridge inversion associated with LC filter is applied on the AC side. While the forward conversion part is operated at M-type high frequency sinusoidal pulse width modulation, the full bridge inversion part is switched at utility frequency. A step-up transformer is used not only to isolate the input from the output but also increase the voltage level from the DC input to the AC output. Except simplicity in structure, advantages of the proposed inverter include zero voltage switching for main and auxiliary switches in the forward converter, low switching losses in the full-bridge inverter, and regeneration of leakage magnetic energy in the transformer through resonance.
To realize the inverter, an independent active clamp forward converter with rating 150W/24Vdc,in/200Vdc,out is constructed first. The theoretical analysis and simulation experience gained from the converter is then implanted to design and implement the micro-inverter with rating 200W/24Vdc,in /110Vac based on the device of 32-bits digital signal processor TMS320F28027. For stand-alone application, the inverter is controlled by AC voltage feedback. For grid-connected operation, the AC waveform of load current is monitored to ensure high power factor is maintained at the interconnection of inverter output and utility network. As a result, the experimental measurements confirm the theoretical prediction. All the inverter switches can be transited at zero voltage over full power range. The inverter efficiency reaches as high as 88.3% and the output power factor is above 99%
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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<br>國立雲林科技大學<br>電機工程系碩士班<br>95<br>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.
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Wu, Yan-Ting, and 吳彥霆. "Research and Implementation of an Active-Clamp Forward Inverter." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/en39rp.
Full textAbstract:
碩士<br>義守大學<br>電機工程學系<br>107<br>This thesis proposes an active-clamp forward inverter. The proposed inverter is developed with an active-clamp forward dc-dc converter, and then connecting with an H-bridge unfolding circuit to output low-frequency voltage. Because the transformer works in the first and third quadrants, it can reduce the volume of the core and the cost. This inverter solves the limitation of duty ratio and the voltage stress on the main switch by resting the flux of transformer wih the auxiliary switch and the clamp capacitor. The zero voltage switching (ZVS) is achieved by the resonant elements, the main switch and auxiliary switch. The zero voltage switching (ZVS) can effectively reduce the switching loss. The system uses the digital signal processor dsPIC30F4011, providing multiple sets of SPWM control signals, simplifying circuit complexity. Finally, a 150W prototype circuit is fabricated for the active-clamp forward inverter. The simulated and experimental results are measured to verify the correctness and feasibility of the proposed inverter.
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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<br>國立雲林科技大學<br>電機工程系碩士班<br>93<br>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.
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Huang, Jhao-Cyuan, and 黃昭銓. "Soft switching Flyback Converter with an Active-Clamp Circuit." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/93831458333763774295.
Full textAbstract:
碩士<br>南台科技大學<br>電機工程系<br>98<br>The traditional pulse-width-modulated flyback converter power switch has serious electromagnetic interference (EMI) and lower conversion efficiencies problems due to the hard-switching operations. This paper produces a soft switching flyback converter with an active-clamp circuit, the traditional pulse-width-modulated flyback converter with a active clamp circuit to achieve zero-voltage-switching (ZVS) at both main and auxiliary switches, the active-clamp circuit can reduce most of switching loss and voltage spikes across the switches and improve the overall efficiency of the converter. The theoretical analysis of soft switching flyback converter with an active-clamp circuit is verified exactly by a prototype of 120W with 100V input voltage, 24V output voltage and 50kHz operated frequency. During full load condition experimental results showed an 82.3% efficiency.