[毕业设计精品]基于SG3525设计单相正弦波SPWM逆变电源外文翻译

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1、外文翻译外文文献Switched-mode power supplyA switched-mode power supply (also switching-mode power supply, SMPS, or simply switcher) is an electronic power supply unit (PSU) that incorporates a switching regulator. While a linear regulator maintains the desired output voltage by dissipating excess power in a

2、 pass power transistor, the switched-mode power supply switches a power transistor between saturation (full on) and cutoff (completely off) with a variable duty cycle whose average is the desired output voltage. It switches at a much-higher frequency (tens to hundreds of kHz) than that of the AC lin

3、e (mains), which means that the transformer that it feeds can be much smaller than one connected directly to the line/mains. Switching creates a rectangular waveform that typically goes to the primary of the transformer; typically several secondaries feed rectifiers, series inductors, and filter cap

4、acitors to provide various DC outputs with low ripple.The main advantage of this method is greater efficiency because the switching transistor dissipates little power in the saturated state and the off state compared to the semiconducting state (active region). Other advantages include smaller size

5、and lighter weight (from the elimination of low frequency transformers which have a high weight) and lower heat generation due to higher efficiency. Disadvantages include greater complexity, the generation of high amplitude, high frequency energy that the low-pass filter must block to avoid electrom

6、agnetic interference (EMI), and a ripple voltage at the switching frequency and the harmonic frequencies thereof.A note about terminologyAlthough the term power supply has been in use since radios were first powered from the line/mains, that does not mean that it is a source of power, in the sense t

7、hat a battery provides power. It is simply a device that (usually) accepts commercial AC power and provides one or more DC outputs. It would be more correctly referred to as a power converter, but long usage has established the term.ClassificationSMPS can be classified into four types according to t

8、he input and output waveforms:AC in, DC out: rectifier, off-line converter input stage DC in, DC out: voltage converter, or current converter, or DC to DC converter AC in, AC out: frequency changer, cycloconverter, transformer DC in, AC out: inverterInput rectifier stageIf the SMPS has an AC input,

9、then the first stage is to convert the input to DC. This is called rectification. The rectifier circuit can be configured as a voltage doubler by the addition of a switch operated either manually or automatically. This is a feature of larger supplies to permit operation from nominally 120 volt or 24

10、0 volt supplies. The rectifier produces an unregulated DC voltage which is then sent to a large filter capacitor. The current drawn from the mains supply by this rectifier circuit occurs in short pulses around the AC voltage peaks. These pulses have significant high frequency energy which reduces th

11、e power factor. Special control techniques can be employed by the following SMPS to force the average input current to follow the sinusoidal shape of the AC input voltage thus the designer should try correcting the power factor. An SMPS with a DC input does not require this stage. An SMPS designed f

12、or AC input can often be run from a DC supply (for 230V AC this would be 330V DC), as the DC passes through the rectifier stage unchanged. Its however advisable to consult the manual before trying this, though most supplies are quite capable of such operation even though nothing is mentioned in the

13、documentation. However, this type of use may be harmful to the rectifier stage as it will only utilize half of diodes in the rectifier for the full load. This may result in overheating of these components, and cause them to fail prematurely.If an input range switch is used, the rectifier stage is us

14、ually configured to operate as a voltage doubler when operating on the low voltage (120 VAC) range and as a straight rectifier when operating on the high voltage (240 VAC) range. If an input range switch is not used, then a full-wave rectifier is usually used and the downstream inverter stage is sim

15、ply designed to be flexible enough to accept the wide range of dc voltages that will be produced by the rectifier stage. In higher-power SMPSs, some form of automatic range switching may be used.Inverter stageThe inverter stage converts DC, whether directly from the input or from the rectifier stage

16、 described above, to AC by running it through a power oscillator, whose output transformer is very small with few windings at a frequency of tens or hundreds of kilohertz (kHz). The frequency is usually chosen to be above 20 kHz, to make it inaudible to humans. The output voltage is optically couple

17、d to the input and thus very tightly controlled. The switching is implemented as a multistage (to achieve high gain) MOSFET amplifier. MOSFETs are a type of transistor with a low on-resistance and a high current-handling capacity. Since only the last stage has a large duty cycle, previous stages can

18、 be implemented by bipolar transistors leading to roughly the same efficiency. The second last stage needs to be of a complementary design, where one transistor charges the last MOSFET and another one discharges the MOSFET. A design using a resistor would run idle most of the time and reduce efficie

19、ncy. All earlier stages do not weight into efficiency because power decreases by a factor of 10 for every stage (going backwards) and thus the earlier stages are responsible for at most 1% of the efficiency. This section refers to the block marked Chopper in the block diagram.Voltage converter and o

20、utput rectifierIf the output is required to be isolated from the input, as is usually the case in mains power supplies, the inverted AC is used to drive the primary winding of a high-frequency transformer. This converts the voltage up or down to the required output level on its secondary winding. Th

21、e output transformer in the block diagram serves this purpose. If a DC output is required, the AC output from the transformer is rectified. For output voltages above ten volts or so, ordinary silicon diodes are commonly used. For lower voltages, Schottky diodes are commonly used as the rectifier ele

22、ments; they have the advantages of faster recovery times than silicon diodes (allowing low-loss operation at higher frequencies) and a lower voltage drop when conducting. For even lower output voltages, MOSFETs may be used as synchronous rectifiers; compared to Schottky diodes, these have even lower

23、 conducting state voltage drops. The rectified output is then smoothed by a filter consisting of inductors and capacitors. For higher switching frequencies, components with lower capacitance and inductance are needed. Simpler, non-isolated power supplies contain an inductor instead of a transformer.

24、 This type includes boost converters, buck converters, and the so called buck-boost converters. These belong to the simplest class of single input, single output converters which utilize one inductor and one active switch. The buck converter reduces the input voltage in direct proportion to the rati

25、o of conductive time to the total switching period, called the duty cycle. For example an ideal buck converter with a 10 V input operating at a 50% duty cycle will produce an average output voltage of 5 V. A feedback control loop is employed to regulate the output voltage by varying the duty cycle t

26、o compensate for variations in input voltage. The output voltage of a boost converter is always greater than the input voltage and the buck-boost output voltage is inverted but can be greater than, equal to, or less than the magnitude of its input voltage. There are many variations and extensions to

27、 this class of converters but these three form the basis of almost all isolated and non-isolated DC to DC converters. By adding a second inductor the uk and SEPIC converters can be implemented, or, by adding additional active switches, various bridge converters can be realised. Other types of SMPSs

28、use a capacitor-diode voltage multiplier instead of inductors and transformers. These are mostly used for generating high voltages at low currents (Cockcroft-Walton generator). The low voltage variant is called charge pump.RegulationA feedback circuit monitors the output voltage and compares it with

29、 a reference voltage, which is set manually or electronically to the desired output. If there is an error in the output voltage, the feedback circuit compensates by adjusting the timing with which the MOSFETs are switched on and off. This part of the power supply is called the switching regulator. T

30、he Chopper controller shown in the block diagram serves this purpose. Depending on design/safety requirements, the controller may or may not contain an isolation mechanism (such as opto-couplers) to isolate it from the DC output. Switching supplies in computers, TVs and VCRs have these opto-couplers

31、 to tightly control the output voltage.Open-loop regulators do not have a feedback circuit. Instead, they rely on feeding a constant voltage to the input of the transformer or inductor, and assume that the output will be correct. Regulated designs compensate for the parasitic capacitance of the tran

32、sformer or coil. Monopolar designs also compensate for the magnetic hysteresis of the core.The feedback circuit needs power to run before it can generate power, so an additional non-switching power-supply for stand-by is added.Transformer designSMPS transformers run at high frequency. Most of the co

33、st savings (and space savings) in off-line power supplies come from the fact that a high frequency transformer is much smaller than the 50/60 Hz transformers formerly used.There are several differences in the design of transformers for 50 Hz vs 500 kHz. Firstly a low frequency transformer usually tr

34、ansfers energy through its core (soft iron), while the (usually ferrite) core of a high frequency transformer limits leakage. Since the waveforms in a SMPS are generally high speed (PWM square waves), the wiring must be capable of supporting high harmonics of the base frequency due to the skin effec

35、t, which is a major source of power loss.Power factorSimple off-line switched mode power supplies incorporate a simple full wave rectifier connected to a large energy storing capacitor. Such SMPSs draw current from the AC line in short pulses when the mains instantaneous voltage exceeds the voltage

36、across this capacitor. During the remaining portion of the AC cycle the capacitor provides energy to the power supply.As a result, the input current of such basic switched mode power supplies has high harmonic content and relatively low power factor. This creates extra load on utility lines, increas

37、es heating of the utility transformers and standard AC electric motors, and may cause stability problems in some applications such as in emergency generator systems or aircraft generators. Harmonics can be removed through the use of filter banks but the filtering is expensive, and the power utility

38、may require a business with a very low power factor to purchase and install the filtering onsite.In 2001 the European Union put into effect the standard IEC/EN61000-3-2 to set limits on the harmonics of the AC input current up to the 40th harmonic for equipment above 75 W. The standard defines four

39、classes of equipment depending on its type and current waveform. The most rigorous limits (class D) are established for personal computers, computer monitors, and TV receivers. In order to comply with these requirements modern switched-mode power supplies normally include an additional power factor

40、correction (PFC) stage.Putting a current regulated boost chopper stage after the off-line rectifier (to charge the storage capacitor) can help correct the power factor, but increases the complexity (and cost).Quasiresonant ZCS/ZVSA quasiresonant ZCS/ZVS switch (Zero Current/Zero Voltage) is a design

41、 where each switch cycle delivers a quantized packet of energy to the converter output, and switch turn-on and turn-off occurs at zero current and voltage, resulting in an essentially lossless switch.EfficiencyHigher input voltage and synchronous rectification mode makes the conversion process more

42、efficient. Higher switch frequency allows component size to be shrunk, but suffer from radio frequency (RF) properties on the other hand. The power consumption of the controller also has to be taken into account.ApplicationsSwitched-mode PSUs in domestic products such as personal computers often hav

43、e universal inputs, meaning that they can accept power from most mains supplies throughout the world, with rated frequencies from 50 Hz to 60 Hz and voltages from 100 V to 240 V (although a manual voltage range switch may be required). In practice they will operate from a much wider frequency range

44、and often from a DC supply as well. In 2006, at an Intel Developers Forum, Google engineers proposed the use of a single 12 V supply inside PCs, due to the high efficiency of switch mode supplies directly on the PCB.Most modern desktop and laptop computers already have a DC-DC converter on the mothe

45、rboard, to step down the voltage from the PSU or the battery to the CPU core voltage, as low as 0.8 V for a low voltage CPU to 1.2-1.5 V for a desktop CPU as of 2007. Most laptop computers also have a DC-AC inverter to step up the voltage from the battery to drive the backlight, typically around 100

46、0 Vrms.Certain applications, such as in automobile industry where ordinary cars often use 12 V DC and in some industrial settings, DC supply is chosen to avoid hum and interference and ease the integration of capacitors and batteries used to buffer the voltage. Most small aircraft use 28 V DC, but l

47、arger aircraft like Boeing-747 often use up to 90 kVA 3-phase at 200 V AC 400 Hz, though they often have a DC bus as well. Even fighter planes like F-16 use 400 Hz power. The MD-81 airplane has an 115/200 V 400 Hz AC and 28 V DC power system generated by three 40 kVA AC generators. Helicopters also

48、use the 28 V DC system. Some submarines like the Soviet Alfa class submarine utilized two synchronous generators providing a variable three-phase current, 2 x 1500 kW, 400 V, 400 Hz. The space shuttle uses three fuel cells generating 30 - 36 V DC. Some is converted into 400 Hz AC power and 28 V DC p

49、ower. The International Space Station uses 120 V DC power. Larger trucks uses 24 V DC.See also: Avionics, Airplane ground supportIn the case of TV sets, for example, one can test the excellent regulation of the power supply by using a variac. For example, in some models made by Philips, the power su

50、pply starts when the voltage reaches around 90 volts. From there, one can change the voltage with the variac, and go as low as 40 volts and as high as 260 (known such case that voltage was 360), and the image will show absolutely no alterations.TerminologyThe term switchmode was widely used until Mo

51、torola trademarked SWITCHMODE(TM), for products aimed at the switching-mode power supply market, and started to enforce their trademark.外文翻译开关模式电源开关模式电源（也开关式电源，开关电源，或只是交换机）是一种电子电源供应器（电源），包含了开关稳压器。虽然线性稳压保持理想的输出电压超过电源的耗散在通过功率晶体管的开关模式电源开关功率晶体管饱和度之间，并断开（完全关闭），可变占空比是其平均理想的输出电压。它的开关在一个非常高的频率（几十甚至几百千赫）比交流的

52、频率要高，相当于变压器，可充当远距离传输电源。创建一个矩形开关波形，通常涉及到的主要的变压器;通常几个二级整流器，一系列电感、电容和滤波提供各种直流输出低纹波。主要利用这一方法提高效率，因为开关晶体管功耗小、功率大，半导体为关闭状态（有源区）。其他优势包括更小的尺寸和较轻的重量（从消除低频变压器具有高体重）和低热量的产生，还有更高的效率。缺点包括更大的复杂性，产生高振幅，高频率能量，必须加低通滤波器，以避免电磁干扰 （ EMI ）之类，和纹波电压的开关频率和谐波频率不足。 有关术语的说明虽然“电源一词”开始出现于无线电的供电线路/主干线，这并不意味着它是力量的源泉，而是作为一个电池提供电源。这

53、是一个这直接由公网交流供电，提供一个或多个直流输出的设备。更确切地可将其称为电源转换器，但可长时间不间断使用。分类 开关电源可分为四种类型根据输入和输出波形： 交流直流：整流器，离线转换器输入级 直流直流：电压转换器，或电流转换器，或直流对直流转换器 交流交流：变频器，变频，变压 直流交流：逆变器 输入整流器阶段 如果有一个开关电源AC输入，然后在第一阶段把交流变成直流输出。这就是所谓的整流。整流电路可配置一个电压倍增，增加了一个开关操作手动或自动。这是一个较大的特点，这类产品允许用电范围从120V到240V。整流器产生稳压直流电压，然后通过一个大型滤波电容器。目前从电源的这一整流电路中出现的

54、短脉冲交流电压峰值来看。这些脉冲产生重大的高频能量，从而降低了功率因数。特别控制技术可以采用下列开关电源，以迫使平均输入电流跟踪正弦形状的交流输入电压，因此，设计师应设法纠正功率因数。一个开关电源与DC输入并不需要这个阶段。一个开关电源设计的AC输入然后变为直流供电（将230V交流变为330V直流） ，直流经过整流阶段不变。这是可取的协商，但该手册在尝试此动作，尽管大多数供应是有相当的能力等操作，即使没有提到的文件中。然而，这种类型的使用可能有害整流阶段，因为它只能利用二极管整流的满负荷的一半。这可能导致器件过热，并导致电源受到损害。 如果开关电源在输入范围内使用，整流器阶段通常配置一个电压补

55、偿作业时的低电压（120VAC）范围和作为直整流作业时的高电压（240VAC）的范围。如果开关电源没有在输入范围内使用，而是为了有足够的灵活性采用全波整流的下游逆变阶段，以通过整流器产生广泛的直流电压。在高功率开关模式电源 ，有些可以作为自动开关来使用。逆变阶段逆变直流转换阶段，无论是直接输入或从整流阶段输入，要变为交流需要通过一个电源振荡器，其输出变压器有很少的绕组，频率为几十或几百千赫（ kHz ） 。频率通常选择将超过20千赫，使人们察觉不到。输出电压是光耦合输入，从而可以非常严格的控制。开关是实施一个多倍放大能力（以实现高增益）的MOSFET。 MOSFET的是一种有低导通、高电流能力

56、的晶体管。因为只有最后一个阶段有一个大的占空比，可在前几个阶段实施双极晶体管导致大致相同的效率。第二个最后阶段需要一个相辅相成的设计，在一个晶体管后接一个相同的MOSFET和一个放电MOSFET的。设计使用一个电阻可以运行大部分的空闲时间，降低效率。所有早期阶段不能达到很好的效率，因为每一个阶段功耗都会降低了10倍，从而早期阶段负责最多产生1的效率。电压转换器和输出整流器 如果输出要与输入分开，常常作为工作电路提供主电源。逆变交流是用来驱动主要绕组的高频变压器。这种转换的电压上升或下降到所需的输出电平可在其二次绕组。如果需要输出直流，纠正变压器输出的交流。输出电压为10伏或10V以上的话，常用

57、普通硅二极管。对于较低的电压，肖特基二极管时常用的整流元件;它的优势，恢复时间比硅二极管更快（允许低损耗运行在更高的频率）和可以在电压下降时进行。甚至输出电压更低的MOSFET可作为同步整流器;与肖特基二极管相比，它们可将电压控制在较低范围。 经过整流后的电压输出较平滑，然后通过一个电感器和电容器组成的过滤器。对于更高的开关频率，较低的电容和电感元件是必要的。 简单的说，非隔离式电源包含一个电感，而不是变压器。这种类型的电源包括升压转换器，降压转换器，以及所谓的升压转换器。这些属于最简单的一类单输入，单输出转换器，它利用一个电感器和一个有效的开关。降低的降压转换器的输入电压的比率传导时间与总开

58、关期间成正比，这就是所谓的占空比。例如，一个理想的降压转换器与输入为10 V运行在50 占空比，将产生平均输出为5V电压。反馈控制回路是用来调节输出电压，通过改变占空比来弥补投入的变化电压。输出电压的升压转换器总是大于输入电压的升压输出电压反转，但可能大于，等于或小于其规模输入电压。这一类的转换器有许多的变化和扩展，但是这三种形式都是基于几乎所有的隔离和非隔离式DC直流转换器。通过增加第二个电感的CUK和SEPIC整流器，或者通过增加额外的积极开关，各种桥变换器可以实现。其他类型的开关模式电源是使用电容二极管电压倍增而不是电感器和变压器。这些都是主要用于产生高电压低电流（克罗夫特-沃尔顿发电机

59、）。低电压变异被称为电荷泵。条例 监测反馈电路的输出电压，并与它的参考电压相比较，期望设置手动的或电子的输出。如果有一个错误的输出电压，反馈电路补偿调整的时机与该MOSFET的是接通或关断。这部分的电力供应被称为开关稳压器。根据安全设计的要求，控制器可能不会只包含一个孤立的隔离机制（如光耦合器）直流输出。电脑，电视机和录像机用品的开关电源中的光耦合器严格控制输出电压。 开环监管没有反馈电路。相反，他们依赖于持续恒定电压和输入变压器或电感，并承担的输出将会是正弦的。设计调节补偿寄生电容的变压器或线圈。单极设计也弥补磁滞回的核心。 反馈电路需求的运行功率，然后才可以发电，从而增加非开关电源。变压器

60、设计 开关电源变压器的运行在高频率。大部分的线性电源成本节省（又节省空间）在来自这样一个事实，即高频变压器使用的频率是远小于50/60赫兹。 有几个不同的设计，变压器50赫兹与500千赫。首先低频变压器传输能量通常通过其核心（软铁） ，而（通常铁氧体）核心的高频变压器限制泄漏。由于一个开关电源波形在一般高速（脉宽调制方波），线路必须能够支持高次谐波的基频由于集肤效应，这是一个功率损耗的主要来源，。功率因数 简单线性开关式电源纳入一个简单的全波整流电路连接到一个大型能源储存电容器。这种开关电源目前来自AC线短脉冲的瞬时电压超过电源电压在此电容。在余下的部分交流周期电容器提供能源的电力供应。 最后

61、，输入电流等基本开关式电源的高次谐波含量和相对较低的功率因数。这造成额外的负荷效用线，增加暖气的实用变压器和标准交流电动机，并可能引起的稳定性问题在一些应用，如在应急发电机系统或飞机的发电机。谐波可以删除通过使用滤波器的过滤，但非常昂贵，以及电力企业可能需要一个非常低的功率因数，以购买和安装过滤现场。 在2001年欧洲联盟实施的标准IEC/EN61000-3-2设限的谐波的交流输入电流谐波的第40次以上的设备75美国标准的定义四类设备根据其类型和电流波形。最严格的限制（ D类）都建立了个人电脑，电脑显示器，电视接收器。为了符合这些要求的现代开关模式电源供应器通常包括一个额外的功率因数校正（ P

62、FC ）的阶段。 把目前的监管提高阶段后，直升机离线整流器（收取存储电容器）可帮助正确的功率因数，但增加了复杂性（和成本） 。Quasiresonant谐振/开关 一个谐振/零电压开关（零电流/零电压）是一种设计的“每个开关周期提供了一个量化包的能量转换器输出，并切换开启和关闭发生在零电流和电压，导致基本上无损开关。 “ 效率 较高的输入电压在同步整流模式转换过程中更有效率。较高开关频率允许元件尺寸缩小，但遭受的射频（ RF ）性能另一方面。耗电量的控制器也必须加以考虑。应用 开关模式电源的产品在国内也有很多应用，如将它们大量应用与个人电脑中，这意味着它们可以适用于世界各地的电路中，额定频率从

63、50赫兹到60赫兹，电压从100伏至240伏（虽然可能需要手动调节开关电压范围）。他们将在实践中适用于更广泛的频率范围，而且往往也可以由直流电源供电。2006年，在英特尔开发商论坛，谷歌工程师建议使用一个单一的12 V电源在PC ，高效率的开关模式用品直接在PCB上。 最现代化的台式和笔记本电脑已经有一个DC-DC转换器在主板上，电压从电源或电池送往核心CPU，CPU的最低电压为0.8 V，到2007年台式电脑的CPU电压在1.21.5之间。大多数笔记本电脑也有一架DC - AC变换器加紧电压由电池来驱动背光，通常约1000 Vrms 。 某些应用程序，如在汽车行业，普通汽车经常使用12伏直流

64、电，在某些工业环境中，直流电源选择，以避免哼声和干涉和易用性的一体化电容器和电池用来缓冲的电压。大多数小飞机使用28伏直流电，但大型飞机像波音747通常使用了90千伏安3相200 V交流400赫兹，但他们往往有一个直流母线以及。即使像战斗机F - 16型使用400 Hz电源。于MD - 81飞机有二百分之一百一十五交流V 400赫兹和28 V直流电源系统产生的3个40千伏安交流发电机。直升机还使用28伏直流电系统。一些潜艇像苏联阿尔法级潜艇利用两个同步发电机提供一个变量三相电流， 2 1500千瓦， 400伏， 400赫兹。航天飞机使用的燃料电池发电3 30 - 36伏直流电。有些被转换成400赫兹交流电源和28 V直流电源。在国际空间站使用120伏直流电源。大卡车使用24伏直流电。 另见：航空电子设备，飞机地面支持 如电视机，例如，一个可以测试的出色调节电源使用variac 。例如，在一些模型所作的飞利浦，电源启动时，电压达到90伏特。从那里，人们可以改变电压的variac ，并前往低至40伏特，高260 （称为这种情况下，电压为360 ） ，图像将显示绝对没有任何改变。术语 开关模式这个词开始作为术语应用还是很广泛的，直到摩托罗拉将其注册为商标，将这种开关模式的电源市场化，并开始强化他们的商标。开关式电源，开关电源，开关稳压器，并指这种类型的电力供应。11