开关电源文献11

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开关电源小论文

1.开关电源研究的背景及意义现实生活中常用的电源，可以分为发出电能的电源和变换电能的电源两大类。

我们把输人和输出都是电能的电源称之为变换电能的电源。

开关电源就是属于变换电能的电源，此种电源就是电路中的电力电子器件工作在开关状态的电源。

开关电源的前身是线性稳压电源。

在我们生活中，大多数电子装置、电气控制设备的工作电源是直流电源。

在开关电源出现之前，这些装置的工作电源都采用线性稳压电源。

在20世纪50年代，美国宇航局以小型化、重量轻为目标,为搭载火箭而开发了开关电源。

在半个多世纪的电力电子技术发展历程中,开关电源因具有体积小、重量轻、效率高、发热量低、性能稳定等优点而逐渐取代传统技术制造的相控稳压电源,并广泛应用于电子整机设备中。

在现代社会,电子信息设备与人们的生活、工作的关系越来越密切,而所有的电子设备都离不开电源。

高速发展的计算机技术带领人类进入了信息社会,同时也促进了电源技术的迅速发展。

电源技术的精髓是电能变换,即利用电能变换技术,将市电或电池等一次电源变换成适用于各种用电对象的二次电源。

开关电源技术属于电力电子技术,它运用功率变换器进行电能变换。

经过变换的电能,可以满足各种用电需求。

由于其高效节能可带来巨大经济效益,因而引起社会各方面的重视而得到迅速推广。

2.国内外研究现状及发展趋势开关电源真正的发展是从70年代开始的,在此期间系统的电力电子理论的确立。

电力电子理论为开关电源的发展提供了一个良好而必需的基础。

但在产品应用的初期,存在开关频率低(20kHz以下)、功率密度比较低、可靠性较差的缺点。

因此开关电源主要的发展方向,是针对上述缺点不断加以改善。

大功率场效应管(MOSFET)及绝缘栅晶体管(IGBT)等器材的出现为高频和大功率变换器提供了极有利的条件。

新的器件和新的拓扑理论的出现使得开关电源技术日趋可靠、成熟、经济、适用。

开关电源目前的发展,主要朝着更高的功能密度和变换效率及更好的动态特性；更好的环保性能；智能化与高可靠性；更广泛的应用等方向发展。

反激式开关电源（毕业论文）

反激式开关电源（毕业论⽂）随着电⼒电⼦技术的发展，开关电源的应⽤越来越⼴泛。

反激式开关电源以其设计简单，体积⼩巧等优势，⼴泛应⽤于⼩功率场合。

开关电源以其⼩型、轻量和⾼效率的特点，被⼴泛地应⽤于各种电⽓设备和系统中，其性能的优劣直接关系到整个系统功能的实现。

开关稳压电源有多种类型，其中单端反激式开关电源由于具有线路简单，所需要的元器件少，能够提供多路隔离输出等优点⽽⼴泛应⽤于⼩功率电源领域。

传统的反激式开关电源⼀般由PWM控制芯⽚(如UC3842)和功率开关管(频率较⾼时⼀般使⽤MOSFET)组成，PWM芯⽚控制环路设计复杂，容易造成系统⼯作不稳定，功率开关管有时需要外加驱动电路。

⾼效率与⼩型化在⼀定程度上是互相限制的，因为实现⾼效率会要求电路有相当的复杂度，⼤量的器件对⼩型化⼗分不利。

在开关电源设计初期，采⽤的都是分⽴元件，集成度很低，⼤部分电路只能在PCB版上实现，极⼤的限制了⼩型化实现的可能。

⽽且⼤量器件暴露在外，也影响了系统的稳定性。

采⽤近年来，为了实现更⾼的效率和更⼩的体积，开关电源的⼯作频率有了很⼤的提⾼。

⾼⼯作频率能够减⼩外围电感和电容的⼤⼩，从⽽减少系统的体积。

另外，反激变压器的设计也是⼀个难点，其往往导致电源设计周期延长。

随着PI公司⽣产的以TOPSwitch为代表的新⼀代单⽚开关电源的问世，以上诸多问题都得到了很好的解决。

应⽤TOPSwitch-HX设计开关电源，不仅器件更少，结构更简单，发热量更少，⼯作更可靠，采⽤该系列芯⽚已成为⼀种⾼效的反激式开关电源设计⽅案。

关键词：TOPSwitch-HX 反激式变换器⾼频变压器开关电源.第⼀章绪论 (1)⼀、反击式开关电源的背景 (1)⼆、反击式开关电源现状与发展趋势 (2)三、本课题选题意义及所做⼯作 (2)第⼆章反击式开关电源简介 (3)⼀、开关电源的分类 (3)⼆、反击式开关电源的原理 (4)第三章⾼效反激式开关电源系统设计 (5)⼀、提⾼效率的⽅法 (5)⼆、⾼效反激式开关电源的系统设计原理图 (6)三、各个⼦电路的分析设计 (7)第四章反激式开关电源元件选择及其参数 (8)⼀、Topswitch-HX 系列元件简介 (8)⼆、提⾼开关电源效率元件选取⽅法 (10)三、主要参数的计算 (11)第五章设计总结与展望 (13)参考⽂献 (14)致谢 (15)附录 (16)第⼀章绪论⼀、反激式开关电源的背景开关电源的前⾝是线性稳压电源。

开关电源研究综述【文献综述】

文献综述电气工程及自动化开关电源研究综述摘要：文章对开关电源做了较为全面的介绍。

概括了开关电源的背景知识，定义，应用以及较为详细的分类情况。

然后对开关电源的分类以及发展的走势进行了展望。

关键词：开关电源控制电路电路设计1.引言随着电子技术的高速发展，电子系统的应用领域越来越广泛，电子设备的种类也越来越多，电子设备与人们的工作、生活的关系日益密切。

任何电子设备都离不开可靠的电源，它们对电源的要求也越来越高。

电子设备的小型化和低成本使电源以轻、薄、小和高效率为发展方向。

在近半个多世纪的发展过程中，开关电源因具有体积小、重量轻、效率高、发热量低、性能稳定等优点而取代传统技术设计制造的连续工作的线性电源，并广泛应用于电子、电气设备中。

20世纪80年代，计算机全面实现了开关电源化，率先完成了计算机的电源换代。

20世纪90年代，开关电源在电子、电气设备以及家电领域得到了广泛的应用，开关电源技术进入快速发展期。

[1]开关电源是利用现代电力电子技术，控制开关管开通和关断的时间比率，维持稳定输出电压的一种电源，开关电源一般由脉冲宽度调制（PWM）控制IC和MOSFET构成。

[4]开关电源的工作过程相当容易理解，在线性电源中，让功率晶体管工作在线性模式，与线形电源不同的是，PWM开关电源是让功率晶体管工作在导通和关断的状态，在这两种状态中，加在功率晶体管上的伏-安乘积是很小的（在导通时，电压低，电流大；关断时，电压高，电流小）功率器件上的伏安乘积就是功率半导体器件上所产生的损耗。

[2-3]与线性电源相比，PWM开关电源更为效的工作过程是通过“斩波”，即把输入的直流电压斩成幅值等于输入电压幅值的脉冲电压来实现的。

脉冲的占空比由开关电源的控制器来调节。

一旦输入电压被斩成交流方波，其幅值就可以通过变压器来升高或降低。

通过增加变压器的二次绕组数就可以增加输出的电压组数。

最后这些交流波形经过整流滤波后就得到直流输出电压。

[8]开关电源可分为AC/DC和DC/DC两大类，也有AC/AC DC/AC 如逆变器DC/DC变换器现已实现模块化，且设计技术及生产工艺在国内外均已成熟和标准化，并已得到用户的认可，但AC/DC的模块化，因其自身的特性使得在模块化的进程中，遇到较为复杂的技术和工艺制造问题。

开关电源外文文献共5页文档

开关电源与电子技术的飞速发展,电子系统的应用领域越来越广泛,电子设备,有越来越多的人工作以电子设备、生活越来越密切的关系。

任何电子设备都离不开可靠供电电源的需求,他们也越来越高。

电子设备的小型化、低成本的光的力量又瘦,小而高效的为发展方向。

传统的晶体管稳压电源是系列调整连续控制线性稳压电源。

这种传统的稳压电源的技术更加成熟,已经有大量的综合线性稳压电源模块,有稳定的性能好、输出电压波动小、运行可靠等。

但通常需要体积大且沉重的工频变压器和体积和重量是大的过滤器。

在1950年代,美国国家航空和宇宙航行局的小型化、轻重量为目标,为火箭携带开关电源的发展。

在近半个世纪的发展过程中,开关电源因其体积小、重量轻、效率高,适用范围广,电压的优点在电子、控制、计算机等许多领域的电子设备已得到广泛应用。

在1980年代,计算机是由所有开关电源的,第一个完整的计算机发电。

整个1990年代,开关电源在电子、电器、家用电器领域得到广泛、开关电源技术进入快速发展。

此外,大规模集成电路技术,和快速发展,开关电源有了质的飞跃,提高了高频大功率产品的、小型化、模块化的潮流。

电源开关管、PWM控制器和高频变压器是不可或缺的组成部分,开关电源。

传统的开关电源的一般均采用高频大功率开关管的划分及各销,如利用PWM(脉宽调制)集成控制器UC3842 + MOSFET是国内小功率开关电源的设计方法,更流行。

自1970年代以来,出现在许多功能完全集成控制电路、开关电源电路越来越简化,工作频率的不断提高,提高效率,为电力小型化提供更为广阔的发展前景。

三结束离线脉冲宽度调制单片机顶部(三个交换线)将终端时,电源开关MOSFET PWM控制器包在一起,已经成为国际关系的主流,开关电源IC发展。

采用集成电路设计上的开关电源开关,可使电路简单、体积进一步缩小,成本也明显降低单片开关电源有单片集成,最简外围电路,最好的性能指标、没有工作频率变压器能构成一个重要的优势开关电源等PI(以)。

开关稳压电源-文献综述

开关稳压电源设计与实现摘要：本文主要介绍开关电源的概述，开关电源的类型,开关电源的发展方向及类型,单片开关电源的原理及应用。

本设计主要是利用3端单片开关电源芯片TOP223Y,进行小功率的开关稳压电源的设计与制作，主要是用开关电源芯片TOP223Y的脉宽调制技术控制开关管,来调制输出电压，以达到稳定输出的目的,最终设计的电路，主要有输入整流滤波、TOP223Y脉宽调制、高频变压器、电压反馈整流滤波、输出整流滤波五部分组成。

关键词：开关电源/TOP223Y/脉宽调制技术一、引言随着电子设备的高速发展, 电子设备与人们的工作、生活的关系日益密切. 任何电子设备都离不开可靠的电源, 他们对电源的要求也越来越高。

电子设备的小型化和低成本化使电源以轻、薄、小和高效率为发展方向。

20世纪80年代，计算机全面实现了开关电源化, 率先完成计算机的电源换代。

20世纪90年代, 开关电源在电子、电器设备、家电领域得到了广泛应用,开关电源技术进入快速发展时期。

开关电源集成电路具有高集成度、高性价比、最简外围电路、最佳性能指标、能构成高效率无工频变压器的隔离式开关电源等优点。

它于90年代中、后期相继问世后,便显示出强大的生命力,目前它成为国际上开发中、小功率开关电源、精密开关电源及电源模块的优选集成电路。

由它构成的开关电源,在成本上与同等功率的线性稳压电源相当，而电源效率显著提高，体积和重量则大为减小。

这就为新型开关电源的推广与普及，创造了良好条件。

开关电源技术属于电力电子技术，它运用功率变换器进行电能变换，经过变换电能,可以满足各种用电要求。

由于其高效节能可带来巨大经济效益，因而引起社会各方面的重视而得到迅速推广。

随着ＰＷＭ技术的不断发展和完善,开关电源得到了广泛的应用,以往开关电源的设计通常采用控制电路与功率管相分离的拓扑结构,但这种方案存在成本高、系统可靠性低等问题。

美国功率集成公司。

Power Integration Inc开发的TOP Switch系列新型智能高频开关电源集成芯片解决了这些问题，该系列芯片将自启动电路、功率开关管、ＰＷＭ控制电路及保护电路等集成在一起，从而提高了电源的效率，简化了开关电源的设计和新产品的开发，使开关电源发展到一个新的时代。

电气外文文献及翻译--开关电源设计

外文文献：Switching Power Supply DesignSwitching power supply work in high frequency, high pulse state, are analog circuits in a rather special kind. Cloth boards to follow the principle of high-frequency circuit wiring.First, layout:Pulse voltage connection as short as possible, including input switch connected to the transformer, output transformer to the rectifier tube cable. Pulse current loop as small as possible such as the input filter capacitor is returned to the transformer to the switch capacitor negative. Some out-ended output transformers are the output rectifier to the output capacitor back to transformer circuit X capacitor as close as possible to the input switching power supply, input lines should be avoided in parallel with other circuits, should be avoided. Y capacitor should be placed in the chassis ground terminal or FG connectors. A total of touch induction and transformer to maintain a certain distance in order to avoid magnetic coupling. Such as poor handling of feeling in between inductor and transformer plus a shield, over a number of EMC performance for power supply to the greater impact.General the output capacitor can be used the other two a close rectifier output terminal should be close to, can affect the power supply output ripple index, two small capacitor in parallel results should be better than using a large capacitor. Heating devices to maintain a certain distance, and electrolytic capacitors to extend machine life, electrolytic capacitors is the switching power supply bottleneck life, such as transformers, power control, high power resistors and electrolytic to maintain the distance required between the electrolyte leaving space for heat dissipation , conditions permitting, may be placed in the inlet.Control part to pay attention to: Weak signal high impedance circuit connected to sample the feedback loop as short as in the processing as far as possible avoid interference, the current sampling signal circuits, in particular the current control circuit, easy to deal with some unexpected bad The accident, which had some skill,now to 3843 the circuit example shown in Figure (1) Figure 1 better than Yu Figure 2, Figure 2 Zai full time by observing the current waveform oscilloscope Mingxian superimposed spikes, Youyuganrao limited flow ratio design Zhi Dian low, Figure 1 there is no such phenomenon, there are switch drive signal circuit, switch resistance should be close to the switch driver can switch the work to improve the reliability of this and the high DC impedance voltage power MOSFET driver characteristics. Second, routingAlignment of current density: now the majority of electronic circuit board using insulated copper constitute tied. Common PCB copper thickness of 35μm, the alignment value can be obtained in accordance with 1A/mm experience the value of current density, the specific calculations can be found in textbooks. To ensure the alignment principles of mechanical strength should be greater than or equal to the width of 0.3mm (other non-power supply circuit board may be smaller minimum line width). PCB copper thickness of 70μm is also common in switching power supply, then the current density can be higher.Add that, now Changyong circuit board design tool design software generally items such as line width, line spacing, hole size and so dry plate Guo Jin Xing parameters can be set. In the design of circuit boards, design software automatically in accordance with the specifications, can save time, reduce some of the workload and reduce the error rate.Generally higher on the reliability of lines or line density wiring can be used double panel. Characterized by moderate cost, high reliability, to meet most applications.The ranks of some of the power module products are also used plywood, mainly to facilitate integration of power devices such as transformer inductance to optimize wiring, cooling and other power tube. Good consistency with the craft beautiful, transformer cooling good advantage, but its disadvantage is high cost, poor flexibility, only suitable for industrial mass production.Single-sided, the market circulation of almost universal switching power supply using single-sided circuit board, which has the advantage of lower costs in thedesign and production technology are also taken some measures to ensure its performance.Single PCB design today to talk about some experience, as a single panel with low cost, easy-to-manufacture features, the switching power supply circuit has been widely used, because of its side tied only copper, the device's electrical connections, mechanical fixation should rely on the copper layer, the processing must be careful.To ensure good performance of the mechanical structure welding, single-sided pad should be slightly larger to ensure that the copper and substrate tied good focus, and thus will not be shocked when the copper strip, broken off. General welding ring width should be greater than 0.3mm. Pad diameter should be slightly larger than the diameter of the device pins, but not too large, to ensure pin and pad by the solder connection between the shortest distance, plate hole size should not hinder the normal conditions for the degree of investigation, the pad diameter is generally greater than pin diameter 0.1-0.2mm. Multi-pin device to ensure a smooth investigation documents can also be larger.Electrical connection should be as wide as possible, in principle, should be larger than the width of pad diameter, special circumstances should be connected in line with the need to widen the intersection pad (commonly known as Generation tears), to avoid breaking certain conditions, line and pad. Principle of minimum line width should be greater than 0.5mm.Single-board components to be close to the circuit board. Need overhead cooling device to device and circuit board between the pins plus casing, can play a supporting device and increase the dual role of insulation to minimize or avoid external shocks on the pad and the pin junction impact and enhance the firmness of welding. Circuit board supporting the weight of large parts can increase the connection point, can enhance joint strength between the circuit board, such as transformers, power device heat sink.Single-sided welding pins without affecting the surface and the shell spacing of the prior conditions, it can be to stay longer, the advantage of increased strength of welded parts, increase weld area and immediately found a Weld phenomenon. Shearpin long legs, the welding force smaller parts. In Taiwan, the Japanese often use the device pins in the welding area and the circuit board was bent 45 degrees, and then welding process, its reasoning Ibid. Double panel today to talk about the design of some of the issues, in relatively high number of requests, or take the line density of the larger application environments using double-sided PCB, its performance and various indicators of a lot better than a single panel.Two-panel pad as holes have been high intensity metal processing, welding ring smaller than a single panel, the pad hole diameter slightly larger in diameter than pins, as in the welding process solder solution conducive to penetrate through the top hole solder pad to increase the welding reliability. But there is a disadvantage if the hole is too large, wave soldering tin when the jet impact in the lower part of the device may go up, have some flaws.High current handling of alignment, line width in accordance with pre-quote processing, such as the width is not enough to go online in general can be used to increase the thickness of tin plating solution, the method has a good variety of1. Will take the line set to pad property, so that when the circuit board manufacturing solder alignment will not be covered, the whole hot air normally be tin plated.2. In the wiring by placing pads, the pad is set to take in line shape, pay attention to the pad holes set to zero.3. In the solder layer placed on line, this method is the most flexible, but not all PCB manufacturers will understand your intentions, needed captions. Place the line in the solder layer of the site will not coated solder tinning line several methods as above, to note that, if the alignment of a very wide all plated with tin in solder after the solder will bond a lot and distribution is very uneven, affecting appearance. Article tin can be used generally slender width in the 1 ~ 1.5mm, length can be determined according to lines, tin part of the interval 0.5 ~ 1mmDouble-sided circuit board for the layout, the alignment provides a very selective, make wiring more reasonable. On the ground, the power ground and signal ground must be separated, the two to converge in filter capacitors, in order to avoid a large pulsed current through the signal ground connection instability caused by unexpectedfactors, the signal control circuit grounding point as far as possible, a skill, as far as possible the alignment of the non-grounded wiring layer in the same place, the last shop in another layer of earth. Output line through the filter capacitors, the general first, and then to the load, input line must also pass capacitor, to the transformer, the theoretical basis is to ripple through trip filter capacitor.V oltage feedback sampling, in order to avoid high current through the alignment of the feedback voltage on the sampling point must be the most peripheral power output to increase the load effect of target machine.Alignment change from a wiring layer to another wiring layer generally used hole connected, not through the pin pad device to achieve, because the plug in the device may be damaged when the relationship between this connection, there is current in every passage of 1A, at least two through-hole, through hole diameter is greater than the principle of 0.5mm, 0.8mm generally processed ensure reliability.Cooling devices, in some small power supply, the circuit board traces can be and cooling, characterized by the alignment as generous as possible to increase the cooling area is not coated solder, conditions can even be placed over holes, enhanced thermal conductivity .Today to talk about the aluminum plate in the switching power supply application and multilayer printed circuit in the switching power supply applications.Aluminum plate by its own structure, has the following characteristics: very good thermal conductivity, single Mianfu copper, the device can only be placed in tied copper surface, can not open electrical connection hole so as not to place jumper in accordance with a single panel.Aluminum plate is generally placed patch device, switch, the output rectifier heat conduction through the substrate to go out, very low thermal resistance, high reliability can be achieved. Transformer with planar chip structure, but also through substrate cooling, the temperature is lower than the conventional, the same size transformer with a large aluminum plate structure available output power. Aluminum plate jumper bridge approach can be used. Aluminum plate power are generally composed by the two PCB, another one to place the control circuit board, through thephysical connection between the two boards is integrated.As the excellent thermal conductivity of aluminum plate, in a small amount of manual welding more difficult, solder cooling too fast and prone to problems of a simple and practical way of existing, an ironing ordinary iron (preferably temperature regulation function), over and iron for the last, fixed, and temperature to 150 ℃ and above the aluminum plate on the iron, heating time, and then affix the components according to conventional methods and welding, soldering iron temperature is appropriate to the device easy to , is too high when the device may be damaged, or even copper strip aluminum plate, the temperature is too low welding effect is not good, to be flexible.Recent years, with the multi-layer circuit board applications in switching power supply circuit, printed circuit transformer makes it possible, due to multilayer, smaller spacing also can take advantage of Bianya Qi window section, the main circuit board can be re- Add 1-2 formed by the multilayer printed coil to use the window, the purpose of reducing circuit current density, due to adopt printed coil, reducing manual intervention, transformers consistency, surface structure, low leakage inductance, coupling good . Open-type magnetic core, good heat dissipation. Because of its many advantages, is conducive to mass production, it is widely used. But the research and development of large initial investment, not suitable for small-scale health.Switching power supply is divided into, two forms of isolation and non-isolated, isolated here mainly to talk about switching power supply topologies form below, non-specified, are to isolate the power. Isolated power supply in accordance with the structure of different forms, can be divided into two categories: a forward and flyback. Flyback transformer primary side means that when the Vice-edge conduction cut-off, transformer storage. Close of the primary, secondary side conduction, the energy released to the load of work status, general conventional flyback power multiplex, twin-tube is not common. Forward refers to the primary conduction in transformer secondary side while the corresponding output voltage is induced into the load, the direct transfer of energy through the transformer. According to specifications can be divided into conventional forward, including the single-transistor forward, DoubleForward. Half-bridge, bridge circuits are all forward circuit.Forward and flyback circuits have their own characteristics in the process of circuit design to achieve optimal cost-effective, can be applied flexibly. Usually in the low-power flyback can be adopted. Slightly larger forward circuit can use a single tube, medium-power can use Double Forward circuit or half-bridge circuit, low-voltage push-pull circuit, and the half-bridge work in the same state. High power output, generally used bridge circuit, low voltage can be applied push-pull circuit. Flyback power supply because of its simple structure, and to cut the size of a similar size and transformer inductance, the power supply in the medium has been widely applied. Presentation referred to in some flyback power supply can do dozens of watts, output power exceeding 100 watts would be no advantage to them difficult. Under normal circumstances, I think so, but it can not be generalized, PI's TOP chips can do 300 watts, an article describes the flyback power supply can be on the KW, but not seen in kind.Power output and the output voltage level.Flyback power transformer leakage inductance is a critical parameter, because the power needs of the flyback transformer stored energy, to make full use of transformer core, the general must be open in the magnetic circuit air gap, the aim is to change the core hysteresis back line of the slope, so that transformers can withstand the impact of a large pulse current, which is not core into saturation non-linear state, the magnetic circuit in the high reluctance air gap in the state, generated in the magnetic flux leakage is much larger than completely closed magnetic circuit .Transformer coupling between the first pole is the key factor determining the leakage inductance, the coil to be very close as far as possible the first time, the sandwich can be used around the law, but this would increase the distributed capacitance transformer. Use core as core with a long window, can reduce the leakage inductance, such as the use of EE, EF, EER, PQ-based EI type magnetic core effective than good.The duty cycle of flyback power supplies, in principle, the maximum duty cycle of flyback power supply should be less than 0.5, otherwise not easy loopcompensation may be unstable, but there are some exceptions, such as the U.S. PI has introduced the TOP series chip can work under the conditions of duty cycle is greater than 0.5.Duty cycle by the transformer turns ratio to determine former deputy side, I am an anti-shock view is, first determine the reflected voltage (output voltage reflected through the transformer coupling the primary voltage value), reflecting a certain voltage range of voltage increase is duty cycle increases, lower power loss. Reduce the reflected voltage duty cycle decreases, increases power loss. Of course, this is a prerequisite, when the duty cycle increases, it means that the output diode conduction time, in order to maintain output stability, more time will be to ensure that the output capacitor discharge current, the output capacitor will be under even greater high-frequency ripple current erosion, while increasing its heat, which in many circumstances is not allowed.Duty cycle increases, change the transformer turns ratio, transformer leakage inductance will increase, its overall performance change, when the leakage inductance energy large enough, can switch to fully offset the large account space to bring low-loss, no further increase when the meaning of duty, because the leakage inductance may even be too high against the peak voltage breakdown switch. Leakage inductance as large, may make the output ripple, and other electromagnetic indicators deteriorated. When the duty hours, the high RMS current through the switch, transformer primary current rms and lowered the converter efficiency, but can improve the working conditions of the output capacitor to reduce fever. How to determine the transformer reflected voltage (duty cycle)Some netizens said switching power supply feedback loop parameter settings, work status analysis. Since high school mathematics is rather poor, "Automatic Control Theory," almost on the make-up, and for the door is still feeling fear, and now can not write a complete closed-loop system transfer function, zero for the system, the concept of feeling pole vague, see Bode plot is only about to see is a divergence or convergence, so the feedback compensation can not nonsense, but there are a number of recommendations. If you have some mathematical skills, and then have some timeto learn then the University of textbooks, "Principles of Automatic Control" digest look carefully to find out, combined with practical switching power supply circuit, according to the work of state for analysis. Will be harvested, the Forum has a message, "coach feedback loop to study the design, debugging," in which CMG good answer, I think we can reference.Then today, on the duty cycle of flyback power supply (I am concerned about the reflected voltage, consistent with the duty cycle), the duty cycle with the voltage selection switch is related to some early flyback switching power supply using a low pressure tube, such as 600V or 650V AC 220V input power as a switch, perhaps when the production process, high pressure tubes, easy to manufacture, or low-pressure pipes are more reasonable conduction losses and switching characteristics, as this line reflected voltage can not be too high, otherwise the work order to switch the security context of loss of power absorbing circuit is quite impressive.Reflected voltage 600V tube proved not more than 100V, 650V tube reflected voltage not greater than 120V, the leakage inductance voltage spike when the tubes are clamped at 50V 50V working margin. Now that the MOS raise the level of manufacturing process control, flyback power supplies are generally used 700V or 750V or 800-900V the switch. Like this circuit, overvoltage capability against a number of switching transformer reflected voltage can be done a bit higher, the maximum reflected voltage in the 150V is appropriate, to obtain better overall performance.TOP PI's recommendation for the 135V chipset with transient voltage suppression diode clamp. But his evaluation board generally reflected voltage to be lower than the value at around 110V. Both types have their advantages and disadvantages: Category: shortcomings against over-voltage, low duty cycle is small, a large pulse current transformer primary. Advantages: small transformer leakage inductance, electromagnetic radiation and low ripple index higher switch loss, the conversion efficiency is not necessarily lower than the second.The second category: a large number of shortcomings of power loss, a large number of transformer leakage inductance, the ripple worse. Advantages: Some strongagainst over-voltage, large duty cycle, lower transformer losses and efficiency higher.Reflected voltage flyback power supply and a determining factorReflected voltage flyback power supply with a parameter related to that is the output voltage, output voltage, the lower the larger the transformer turns ratio, the greater the transformer leakage inductance, switch to withstand higher voltage breakdown switch is possible to absorb power consumption is higher, has the potential to permanently absorb the circuit power device failure (particularly with transient voltage suppression diode circuits). In the design of low-voltage low-power flyback power output optimization process must be handled with care, its approach has several:1, using a large core of a power level lower leakage inductance, which can improve the low-voltage flyback power conversion efficiency, reduce losses, reduce output ripple and improve multi-output power of the cross regulation in general is common in household appliances with a switch power, such as CD-ROM drive, DVB set-top boxes.2, if the conditions were not increased core, can reduce the reflected voltage, reducing the duty cycle. Reduce the reflected voltage can reduce the leakage inductance but may reduce the power conversion efficiency, which is a contradiction between the two, must have an alternative process to find a suitable point, replace the transformer during the experiment can detect the transformer original side of the anti-peak voltage, peak voltage to minimize the anti-pulse width, and magnitude of the work safety margin increase converter. Generally reflected voltage 110V when appropriate.3, enhance the coupling, reducing losses, the introduction of new technologies, and the routing process, transformers to meet the security specifications will between the primary and secondary side to insulation measures, such as pad tape, plus side air insulation tape. These will affect the performance of transformer leakage inductance, the reality can be used in production around the primary winding secondary wrapping method. Or sub-system with a triple insulated wire wound to remove the insulation between the initial level, can enhance the coupling, even use wide copper winding.The article refers to low voltage output is less than or equal to 5V output, as thistype of small power supply, my experience is that the power output of more than 20W output can use a forward, get the best value for money, of course, this is not the right decision , and personal habits, relationship between the application environment, the next time to talk about the flyback power supply with a magnetic core, magnetic circuit air gap opening some understanding, I hope you receive adequate guidance.Flyback power transformer core magnetization state at work in one way, it needs to open the air gap magnetic circuit, similar to the pulsating direct current sensor. Part of the magnetic coupling through the air gap. Why I understand the principle of open air gap as follows: As the power ferrite also has a similar rectangle of the operating characteristics (hysteresis loop), operating characteristics curve in the Y-axis magnetic induction (B), now the general production process saturation point in 400mT above, the general value in the design of this value should be more appropriate in the 200-300mT, X-axis magnetic field strength (H) the value of current intensity is proportional to the magnetization. Open magnetic circuit air gap equal to the magnetic hysteresis loop to the X axis tilt, in the same magnetic induction intensity, can withstand a greater magnetizing current, equivalent to core store more energy, this energy cut-off switch When spilled into the load through the transformer secondary circuit, flyback power core to open the air gap is twofold. One is to transfer more energy, and the second to prevent the core into saturation.Flyback Power Transformer magnetization state in one way, not only to pass through the magnetic coupling energy, is also responsible for input and output isolation voltage transform multiple roles. Therefore, the treatment gap need to be very careful, the air gap leakage inductance can become too large, increase the hysteresis loss, iron loss, copper loss increases, affecting the power of the whole performance. Air gap is too small has the potential to transformer core saturation, resulting in damage to powerThe so-called flyback power supply is continuous and discontinuous mode transformer working conditions, working in full load condition in the power transformer complete transfer, or incomplete transmission mode. General design of the working environment, conventional flyback power supply should work incontinuous mode, this switch, circuit loss are relatively small, and can reduce the stress of work input and output capacitors, but that there are some exceptions.Requires in particular that: As the characteristics of the flyback power supply is also more suitable for design into a high-voltage power supply, and high-voltage power transformers generally work in discontinuous mode, I understand the need for as high voltage power supply output voltage of the rectifier diodes. Because of the manufacturing process characteristics, high-tension diode, reverse recovery time is long, low speed, the current continuous state, the diode has a positive bias in the recovery, reverse recovery energy loss is very large, is not conducive to converter performance increase, ranging from reduced conversion efficiency, rectifiers, severe fever, weight is even burnt rectifier. As in the intermittent mode, the diode is reverse biased under zero bias, loss can be reduced to a relatively low level. Therefore, high voltage power supply work in discontinuous mode, and the frequency can not be too high.Another type of flyback power supply work in the critical state, the general type of power supply work in FM, or FM-width-modulated dual-mode, a number of low-cost self-excitation power (RCC) is often used this form in order to ensure stable output transformer As the operating frequency, output current or input voltage change, close to the fully loaded transformer is always maintained at between continuous and intermittent, this power is only suitable for small power output, otherwise the handling characteristics of electromagnetic compatibility will be a headache Flyback switching power supply transformer should work in continuous mode, it required relatively large winding inductance, of course, is to some extent continuous, excessive pursuit of absolute continuity is not realistic, may need a great core, very much coil turns, accompanied by a large leakage inductance and distributed capacitance, worth the trouble. So how does this parameter to determine, through repeated practice, and analysis of peer design, I think, in the nominal voltage input, the output reached 50% and 60% transformer from intermittent, continuous state of transition to more appropriate. Or at the highest input voltage state, the full output, the transformer can transition to the continuous state on it.中文译文：开关电源设计开关电源状态，电源工作在高频率，高脉冲的模拟电路的一个比较特殊的一种。

开关电源论文报告罗顺打印版

摘要在阐述BOOST开关电源工作原理的基础上，设计了一个输出电压可调的开关电源电路，针对开关电源设计中所关心的输出电压纹波，开关管场效应的占空比，主要功能器件（开关管、电感、电容、二极管）功率损耗、效率与电感电容取值的关系、效率与电流负载的关系进行了LTspice仿真，并给出了相应的仿真结果，根据仿真的结果及方法可以进一步提高开关电源的效率，关键词：开关电源；Boost变换；LTspice IV。

AbstractA boost converter circuit with sdjustable output voltage is designed on describing zhe principle of switching mode power supply in zhe article.The simulation results are given by LTspice that zhe ripple of output voltage,the swilch duty cycle of switcling FET,the power loss of main function devices(switching FET,inductor,capacitor,and diode),the relationship of efficiency va.values of inductor and capacotor and the relationship of effciency vs.load current which are attended when switch mode power supply designed,the efficiency of switching mode power supply can be further improved according to the simulation measults and ways.Key word:switching mode power supply;boost convvert;LTspice IV.目录1 引言 (3)2 电路的工作状态 (3)3 matlab仿真分析 (4)4系统方案设计 (4)4.1系统方框图 (4)4.2 boost升压电路模型 (4)5 电路参数的计算及元器件选型 (5)5.1 系统要求 (5)5.2 TL494工作原理 (5)5.3 开关频率的计算 (8)5.4 电感值的计算 (8)5.5 二极管选型 (10)6系统总设计原理图 (10)7 设计结果与分析 (11)7.1 测试工具 (11)7.2 比较基准波形图 (11)7.3 TL494输出波形 (11)7.4输出纹波波形 (12)7.5 电感输出波形 (12)7.6 实物图 (13)8实验小结 (14)参考文献 (15)1 引言BOOST 电路又称为升压型电路, 是一种直流- 直流变换电路, 其电路结构如图1 所示。

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v S1 (m ax) = v S2 (m ax) = V
in
3 电路稳态波形分析及主要参数计算
通过电路稳态波形分析, 不仅可得到电路的稳态电压、电流波形, 还可得到该 DC DC 变换器的稳态电压比, 电感电流纹波, 输出电压纹波, 开关器件的电压、电流应力等重要参数。
3. 1 初步分析
© 1995-2005 Tsinghua Tongfang Optical Disc Co., Ltd. All rights reserved.
周伟松, 等: 一种倍流同步整流有源箝位 DC DC 变换器的研究
79
为 S 3 续流而导通; D 4 导通, L 3 完成由主流到续流的过渡; D 3 关断, L 4 完成由续流到主流的过渡; S 4 零电压导通, D 4 关断。从以上分析可以看出, 在 S 1～ S 4 开通时, D 1～～ S 4 实现了零电压开通。 D 4 分别已经导通, 因而 S 1
= ( t3 - t2 ) T S , T S 为开关周期, 则 D ′ 1- D 。 D′
N N = V0 D (1 - D ) D (1 - D ) iS1 (m ax) = I S + iS ( p p)
( 9)
2
=
I0 + N
V in V in DTS (1 - D ) + 2 Lm 2 N L4
1 电路拓扑分析
图 1 为倍流同步整流有源箝位 DC DC 变换器的主电路拓扑图。变换器采用有源箝位电路, V in 为直流输入电压, S 1 为主开关, S 2 为辅助开关, S 3 和～ S 4 均为 N 型M O S 管) , T 为隔 S 4 为同步整流管 ( S 1 离变压器, S 2 和 C 组成有源箝位网络。 D 1～ D 4 代表 S 1～ S 4 的体二极管, C 1～ C 4 代表 S 1～ S 4 的等效结电容, L lk 为 T 的漏感, L m 为 T 的励磁电感, T 1 为理想变压器, 变比为 N 1。工作时 S 1 和 S 2 轮流导通, 当 S 1 关断时, S 2 导通, 箝位电容 C 被并联到 T 的原边, 为漏感电流提供一个低阻抗的无损耗的通路, 从而在每个开关周期中以最小的损耗来吸收和回放电能, 同时变压器 T 铁心磁通又可自动复位。整流电路采用倍流同步整流形式, 同步整流功率 M O SFET S 3 和 S 4 采用自驱动控制; L 3 和 L 4 为滤波电感, C 0 为滤波电容, R 0 为负载等效电阻, 输出电流由 L 3 和 L 4 电流叠加供给, 故称之为倍流同步整流电路。值得注意的是, 通常使用 M O SFET 时, 控制电压加在栅极 ( G ) 和源极 ( S ) 之间, 而 S 3 和 S 4 的控制信号却是加在栅极 ( G ) 和漏极 (D ) 之间。这是因为功率 M O SFET 内部存在一个反并联的体二极管, 控制信号加在 G 和 D 之间就使整流功率 M O SFET 在控制信号为零时具有反向电压阻断能力。传统整流电路工作时, 当滤波电感较小或负载电阻较大或开关频率 f 0 较低时, 将出现电感电流在一个周期结束前就下降到零并一直保持到周期结束
图1 倍流同步整流有源箝位 DC DC 变换器拓扑
的情况, 这就是不连续导电工作模式 [ 4 ]。而同步整流电路只有连续导电工作模式, 原因是功率 M O SFET 导通后具有双向通流能力。其优点是: 电路在全负载范围内, 工作状态均属连续导电模式, 控制电路稳定性好。而传统整流电路往往不适合空载 ( 或轻载) 工作, 需要预先加一固定负载保证最小输出电流, 使电路工作在连续导电模式; 在设计传统整流电路的滤波器时, 为了保证轻载下电流连续, 往往采用较大电感量的滤波电感, 因而在大电流时功耗较大。在对功耗要求较苛刻的设计中, 若采用同步整流电路, 则可以选用较小电感量的滤波电感, 同时增大滤波电容来满足降低输出纹波的要求, 这样可以明显降低滤波器损耗, 提高变换器效率。
清华大学电机工程与应用电子技术系, 北京 100084; 0 北京迪赛通用技术研究所, 北京 100081
文摘为提高低输出电压的 DC DC 变换器的效率, 提出了一种倍流同步整流有源箝位 DC DC 变换器, 电路拓扑主要包括有源箝位电路、隔离变压器和倍流同步整流电路。分析了该变换器的工作原理, 并进行了稳态分析, 给出了各开关器件的电压、电流应力公式。理论分析表明, 该变换器的开关器件的电压应力特性优异, 开关器件均可实现零电压开通, 适用于较宽的输入电压范围和较高的开关频率, 实验样机得到了较高的效率和功率密度。关键词倍流同步整流; 有源箝位; 零电压开关; DC DC 变换器分类号 TM 465
第四阶段: 辅助开关 S 2 关断到主开关 S 1 开始导通 ( t3～ t4 ) 。 t3 时刻, 驱动信号使 S 2 关断, 由于 T 存在漏感, iC 并不立即消失, 而是逐渐减小并为 C 2 充电, 若 L m 较小, 当 v S1 减小到0后, - im v S2 上升, v S1 下降。的值比 i2 N 还大, 电流- iS 企图给 C 1 反向充电, 但由于 D 1 开始导通, 为- iS 提供通路, 此时, 主开关 S 1 可实现零电压导通。整流电路依次经历: S 3 关断, D 3
1- D
=
V inD ı N
分析时的假定条件: 电路中的电感、电容、功率二极管等均是理想的; 输出电压的纹波 M O SFET、 $ v 0 与其平均值 V 0 相比小得多, 认为 v 0 = V 0 , i0 = I 0; 箝位电容 C 上的电压纹波 $ v C 与其平均值 V C 相比也小得多, 认为 v C = V C ; 漏感 L lk 与励磁电感 L m 相比小得多, 认为 L lk = 0。由假定条件可知, 开关转换瞬间完成, 则 t1～ t2 , t3～ t4 时间段均可忽略, 记导通比 D = ( t1 - t0 ) T S ,
( 10)
由式 ( 9) 可知, V 0 一定时, 开关 S 1 和 S 2 的电压应力随 V in 的不同而变化的幅度很小 ( 当导通比 D 从 013～ 0. 7 变化时, 应力值变化范围是 4N V 0～ 4. 76N V 0 ) , 这是有源箝位电路的优点。
比较式 ( 6) 和式 ( 8) 可看出, 倍流同步整流与无倍流的同步整流电路 ( 图1中去掉 L 3 即是) 相比输出滤波电容电流纹波小得多, 这样就减小了滤波电容的负荷; 同时, 电感电流的直流部分 I 3 + I 4 等于负载电流 I 0 , 可见负载电流由 L 3 和 L 4 共同分担, 因此电感的直流工作点比无倍流的同步整流电路低, 有利于降低实际电路中电感的损耗。由图4 (a ) 很容易进一步得到开关电压、电流应力公式, 如
完成由续流到主流的过渡; S 3 零电压导通, D 3 关断。第三阶段: 箝位电路作用阶段 ( t2～ t3 ) , 等效电路见图3 ( b ) 。 t2 时刻起, 由于 D 2 导通, 箝位电容 C 与变压器的原边绕组并联。时刻, S 2 零电压开通, D 2 t2 ′ 随即因导通压降比 S 2 大而截止。 iC 从 D 2 导通时起, 先是对 C 充电, 同时, iC 逐渐减小, 到 tc 时间, iC 减小到0, C 放电, S 2 允许电流 iC 反方向流动。在 t2～ t3 期间, v 1 = - v C , v 2 = - v C N < 0, 因而 S 4 处于截止状态, S 3 处于导通状态, T 1 副边电流 i2 < 0, - i2 通过 L 3 和 S 3 向负载供电 (L 3 主流) , 同时, L 4 的电流 i4 通过负载和 S 3 续流。这一阶段, 励磁电感 L m 将储能释放给负载。
2 电路工作过程分析
图2为开关 S 1 和 S 2 的控制电压时序图。
( a ) t0 ～ t1 阶段等效电路
图2 控制电压时序图
( b ) t2 ～ t3 阶段等效电路
图3 两个主要工作阶段的等效电路 ( 忽略漏感)
下面分4个阶段描述电路的工作过程。第一阶段: 主开关 S 1 导通阶段 ( t0 ～ t1 ) , 等效电路见图3 ( a ) 。在这个阶段, 主开关 S 1 导通, 辅助开关 S 2 截止, 箝位电路断开, 输入电压通过 S 1 加到 T 1 上, 此时 v 1 = V in , v 2 = V in N > 0, 因而 S 4 处于导通状态, S 3 处于截止状态, T 1 副边电流 i2 通过 L 4、 S 4 为负 ( ) 载供电称 L 4 的电流 i4 为主流 , 同时, L 3 的电流 i3 通过负载和 S 4 续流。在此阶段中 V in 供给变换器的能
[3] M O SFET 结构。
本文提出了一种倍流同步整流有源箝位 DC 在48V DC 变换器拓扑结构, 并对其进行分析研究。 5 V ( 30A ) DC DC 变换器模块中应用, 实验结果令人满意, 效率达到 90% , 并实现了模块设计的小型化、薄型化, 尺寸为119mm ×81mm ×12. 7mm 。
1998年第38卷
清华大学学报 ( 自然科学版) Jou rna l of T singhua U n iversity (Sci & T ech )
18 27 第3期第77 ～ 81页
一种倍流同步整流有源箝位 D C D C 变换器的研究
周伟松, 胡蓉芳, 周权0 , 盛立明0
量一部分经变压器传递给负载, 另一部分则转变为变压器的励磁电感 L m 的储能。第二阶段: 主开关 S 1 关断到 D 2 开始导通 ( t1～ t2 ) 。 t1 时刻, S 1 关断, 由于 T 存在漏感, 输入电流 iS 不会立即降为 0, 而是逐渐减小并为 C 1 充电, v S1 上升, v S2 下降; 到 t2 时刻, v S2 下降到0, D 2 开始导通。整流电路依次经历: S 4 关断, D 4 为 S 4 续流而导通; D 3 导通, L 4 完成由主流到续流的过渡; D 4 关断, L 3