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1、<p><b>  Inverter</b></p><p>  1 Introduction</p><p>  An inverter is an electrical device that converts direct current (DC) to alternating current (AC); the converted AC can b

2、e at any required voltage and frequency with the use of appropriate transformers, switching, and control circuits.Solid-state inverters have no moving parts and are used in a wide range of applications, from small switch

3、ing power supplies in computers, to large electric utility high-voltage direct current applications that transport bulk power. Inverters are commonly used to s</p><p>  There are two main types of inverter.

4、The output of a modified sine wave inverter is similar to a square wave output except that the output goes to zero volts for a time before switching positive or negative. It is simple and low cost and is compatible with

5、most electronic devices, except for sensitive or specialized equipment, for example certain laser printers. A pure sine wave inverter produces a nearly perfect sine wave output (<3% total harmonic distortion) that is

6、essentially the same as u</p><p>  2 Applications</p><p>  2.1 DC power source utilization</p><p>  An inverter converts the DC electricity from sources such as batteries, solar p

7、anels, or fuel cells to AC electricity. The electricity can be at any required voltage; in particular it can operate AC equipment designed for mains operation, or rectified to produce DC at any desired voltageGrid tie in

8、verters can feed energy back into the distribution network because they produce alternating current with the same wave shape and frequency as supplied by the distribution system. They can also switch o</p><p&g

9、t;  2.2 Uninterruptible power supplies</p><p>  An uninterruptible power supply (UPS) uses batteries and an inverter to supply AC power when main power is not available. When main power is restored, a recti

10、fier supplies DC power to recharge the batteries.</p><p>  2.3 Induction heating</p><p>  Inverters convert low frequency main AC power to a higher frequency for use in induction heating. To do

11、 this, AC power is first rectified to provide DC power. The inverter then changes the DC power to high frequency AC power. </p><p>  2.4 HVDC power transmission</p><p>  With HVDC power transmi

12、ssion, AC power is rectified and high voltage DC power is transmitted to another location. At the receiving location, an inverter in a static inverter plant converts the power back to AC.</p><p>  2.5 Varia

13、ble-frequency drives</p><p>  A variable-frequency drive controls the operating speed of an AC motor by controlling the frequency and voltage of the power supplied to the motor. An inverter provides the cont

14、rolled power. In most cases, the variable-frequency drive includes a rectifier so that DC power for the inverter can be provided from main AC power. Since an inverter is the key component, variable-frequency drives are s

15、ometimes called inverter drives or just inverters.</p><p>  2.6 Electric vehicle drives</p><p>  Adjustable speed motor control inverters are currently used to power the traction motors in some

16、 electric and diesel-electric rail vehicles as well as some battery electric vehicles and hybrid electric highway vehicles such as the Toyota Prius and Fisker Karma. Various improvements in inverter technology are being

17、developed specifically for electric vehicle applications.[2] In vehicles with regenerative braking, the inverter also takes power from the motor (now acting as a generator) and stores </p><p>  2.7 The gene

18、ral case</p><p>  A transformer allows AC power to be converted to any desired voltage, but at the same frequency. Inverters, plus rectifiers for DC, can be designed to convert from any voltage, AC or DC, to

19、 any other voltage, also AC or DC, at any desired frequency. The output power can never exceed the input power, but efficiencies can be high, with a small proportion of the power dissipated as waste heat. </p><

20、;p>  3 Circuit description </p><p>  3.1 Basic designs </p><p>  In one simple inverter circuit, DC power is connected to a transformer through the centre tap of the primary winding. A sw

21、itch is rapidly switched back and forth to allow current to flow back to the DC source following two alternate paths through one end of the primary winding and then the other. The alternation of the direction of current

22、in the primary winding of the transformer produces alternating current (AC) in the secondary circuit. </p><p>  The electromechanical version of the switching device includes two stationary contacts and a sp

23、ring supported moving contact. The spring holds the movable contact against one of the stationary contacts and an electromagnet pulls the movable contact to the opposite stationary contact. The current in the electromagn

24、et is interrupted by the action of the switch so that the switch continually switches rapidly back and forth. This type of electromechanical inverter switch, called a vibrator or buzzer</p><p>  As they beca

25、me available with adequate power ratings, transistors and various other types of semiconductor switches have been incorporated into inverter circuit designs</p><p>  3.2 Output waveforms</p><p>

26、;  The switch in the simple inverter described above, when not coupled to an output transformer, produces a square voltage waveform due to its simple off and on nature as opposed to the sinusoidal waveform that is the us

27、ual waveform of an AC power supply. Using Fourier analysis, periodic waveforms are represented as the sum of an infinite series of sine waves. The sine wave that has the same frequency as the original waveform is called

28、the fundamental component. The other sine waves, called harmoni</p><p>  The quality of output waveform that is needed from an inverter depends on the characteristics of the connected load. Some loads need a

29、 nearly perfect sine wave voltage supply in order to work properly. Other loads may work quite well with a square wave voltage. </p><p>  3.3 Three phase inverters</p><p>  Three-phase inverter

30、s are used for variable-frequency drive applications and for high power applications such as HVDC power transmission. A basic three-phase inverter consists of three single-phase inverter switches each connected to one of

31、 the three load terminals. For the most basic control scheme, the operation of the three switches is coordinated so that one switch operates at each 60 degree point of the fundamental output waveform. This creates a line

32、-to-line output waveform that has six st</p><p>  4 History</p><p>  4.1 Early inverters</p><p>  From the late nineteenth century through the middle of the twentieth century, DC-

33、to-AC power conversion was accomplished using rotary converters or motor-generator sets (M-G sets). In the early twentieth century, vacuum tubes and gas filled tubes began to be used as switches in inverter circuits. The

34、 most widely used type of tube was the thyratron.</p><p>  The origins of electromechanical inverters explain the source of the term inverter. Early AC-to-DC converters used an induction or synchronous AC mo

35、tor direct-connected to a generator (dynamo) so that the generator's commutator reversed its connections at exactly the right moments to produce DC. A later development is the synchronous converter, in which the moto

36、r and generator windings are combined into one armature, with slip rings at one end and a commutator at the other and only one field fra</p><p>  4.2 Controlled rectifier inverters</p><p>  Sin

37、ce early transistors were not available with sufficient voltage and current ratings for most inverter applications, it was the 1957 introduction of the thyristor or silicon-controlled rectifier (SCR) that initiated the t

38、ransition to solid state inverter circuits.</p><p>  The commutation requirements of SCRs are a key consideration in SCR circuit designs. SCRs do not turn off or commutate automatically when the gate control

39、 signal is shut off. They only turn off when the forward current is reduced to below the minimum holding current, which varies with each kind of SCR, through some external process. For SCRs connected to an AC power sourc

40、e, commutation occurs naturally every time the polarity of the source voltage reverses. SCRs connected to a DC power source us</p><p>  In applications where inverters transfer power from a DC power source t

41、o an AC power source, it is possible to use AC-to-DC controlled rectifier circuits operating in the inversion mode. In the inversion mode, a controlled rectifier circuit operates as a line commutated inverter. This type

42、of operation can be used in HVDC power transmission systems and in regenerative braking operation of motor control systems.</p><p>  Another type of SCR inverter circuit is the current source input (CSI) inv

43、erter. A CSI inverter is the dual of a six-step voltage source inverter. With a current source inverter, the DC power supply is configured as a current source rather than a voltage source. The inverter SCRs are switched

44、in a six-step sequence to direct the current to a three-phase AC load as a stepped current waveform. CSI inverter commutation methods include load commutation and parallel capacitor commutation. With both m</p>&l

45、t;p>  As they have become available in higher voltage and current ratings, semiconductors such as transistors or IGBTs that can be turned off by means of control signals have become the preferred switching components

46、for use in inverter circuits. </p><p>  4.3 Rectifier and inverter pulse numbers</p><p>  Rectifier circuits are often classified by the number of current pulses that flow to the DC side of the

47、 rectifier per cycle of AC input voltage. A single-phase half-wave rectifier is a one-pulse circuit and a single-phase full-wave rectifier is a two-pulse circuit. A three-phase half-wave rectifier is a three-pulse circui

48、t and a three-phase full-wave rectifier is a six-pulse circuit。With three-phase rectifiers, two or more rectifiers are sometimes connected in series or parallel to obtain higher</p><p><b>  逆變器</b&g

49、t;</p><p><b>  1 簡介</b></p><p>  逆變器是一種能將直流電轉(zhuǎn)化為可變的交流電的電子裝置,使用適當(dāng)?shù)淖儔浩?、開關(guān)以及控制電路可以將轉(zhuǎn)化的交流電調(diào)整到任何需要的電壓以及頻率值。</p><p>  固定的逆變器沒有移動部件,其應(yīng)用范圍極其廣泛,從小型計算機開關(guān)電源,到大型電力公司高壓直流電源應(yīng)用,運輸散貨。逆變

50、器通常用于提供從諸如太陽能電池板或電池直流電源轉(zhuǎn)換的交流電源..</p><p>  逆變器有兩種主要類型。對修改后正弦波逆變器輸出是一個類似方波輸出,輸出去除了一時間為零伏特,然后才轉(zhuǎn)到正或負。它的電路簡單而且成本一般較低,并與大多數(shù)電子設(shè)備兼容,除了敏感或?qū)S迷O(shè)備,例如某些激光打印機。純正弦波逆變器產(chǎn)生一個近乎完美的正弦波輸出“(<3%的總諧波失真),它本質(zhì)上與公用事業(yè)電網(wǎng)提供的相同。因此它與所有的交流

51、電子設(shè)備兼容。這是網(wǎng)逆變器配合使用的類型。它的設(shè)計更為復(fù)雜,成本5人以上每單位功率。[1]電逆變器是一種高功率電子振蕩器的10倍。它是如此命名是因為早期機械A(chǔ)C到DC轉(zhuǎn)換器的工作作了相反,因此是“倒“,轉(zhuǎn)換成直流到交流。變頻器的整流執(zhí)行相反的功能</p><p><b>  2 應(yīng)用</b></p><p>  2.1 直流電源利用率</p><

52、;p>  逆變器將直流電,如電池,太陽能電池板,燃料電池等轉(zhuǎn)換為交流電直流電。轉(zhuǎn)換的交流電可以是任意需要大小的交流電,特別是它可以操作交流設(shè)備用于電源操作,或者濾波產(chǎn)生任何需要的直流電壓。</p><p>  配電網(wǎng)絡(luò)逆變器可以將能量反饋到分配網(wǎng)絡(luò),因為他們產(chǎn)生的交流電和分配網(wǎng)絡(luò)提供的交流電的波形和頻率可以是一樣的。而且他們也可以自動關(guān)斷輸出當(dāng)遇到停電事故時。微型逆變器將由個人太陽能電池板產(chǎn)生的直流電轉(zhuǎn)化為

53、交流電并入電網(wǎng)。接從個人的太陽能電池板的電流。它們使用默認(rèn)的輸電網(wǎng)設(shè)計。</p><p>  2.2 不間斷電源</p><p>  不間斷電源(UPS)當(dāng)主電源無法使用時使用電池和逆變器提供交流電源。當(dāng)主電源恢復(fù)時,一個整流器供應(yīng)直流電源對電池進行充電。</p><p><b>  2.3 感應(yīng)加熱</b></p><

54、p>  逆變器將低頻交流電源轉(zhuǎn)化為更高的頻率以用于感應(yīng)加熱使用。要做到這一點,首先交流電源經(jīng)過濾波提供直流電源。該逆變器,然后更改為高頻率的交流電源直流電源。</p><p>  2.4 高壓直流輸電</p><p>  隨著高壓直流輸電,交流電源進行整流和高壓直流電源被傳輸?shù)搅硪粋€位置。在接收的位置,在一個靜止變流器廠將直流電源轉(zhuǎn)換回交流電</p><p>

55、;  2.5 變頻驅(qū)動器</p><p>  一個變頻驅(qū)動控制器通過控制供應(yīng)給電機的電源電壓和頻率來控制交流電機的運行速度。逆變器提供控制信號。在大多數(shù)情況下,變頻驅(qū)動器包括一個整流器,因而提供給逆變器的直流電源可以由交流主電源提供。由于逆變器是關(guān)鍵部件,變頻驅(qū)動器有時也被稱為逆變器驅(qū)動器或只是逆變器</p><p>  2.6 電動汽車驅(qū)動</p><p> 

56、 調(diào)速電動機控制逆變器是目前用于電力牽引在一些電動和柴油電動軌道車輛以及一些電池電動汽車上的電機,如豐田Prius和菲斯克噶瑪混合動力電動汽車高速公路交通工具。在變頻技術(shù)的各項改善措施正在制定專門針對電動車輛的應(yīng)用。與更新制動車輛,還需要從變頻器的電機(現(xiàn)在作為發(fā)電機)和它儲存在電池里的電源。</p><p>  2.7 一般情況下</p><p>  一個變壓器允許交流電源被轉(zhuǎn)換為任何

57、所需的電壓,但是卻在相同的頻率。逆變器,直流加整流器,可以設(shè)計成任何轉(zhuǎn)換電壓,交流或直流,在任何需要的頻率,以任何其他電壓,也可以是交流或直流。輸出功率不能超過輸入功率,但效率可以很高,可以允許作為一部分余熱消耗掉功率很小的一部分。</p><p><b>  3 電路描述</b></p><p><b>  3.1 基本設(shè)計</b><

58、/p><p>  在一個簡單的逆變電路中,直流電源通過初級繞組的中心抽頭連接到變壓器。開關(guān)以極高的頻率來回切換,使電流回流在變壓器的初級繞組里流過一個方向后再向另一個方向流動。初級繞組里電流方向的變化通過變壓器在次級繞組里產(chǎn)生交變電流。 </p><p>  在開關(guān)設(shè)備機電版本包括兩個固定觸點和彈簧支撐移動接觸點。彈簧持有一個可移動的觸體來和固定觸點接觸,電磁鐵拉動可移動的觸體到對面的固定

59、的觸體。在電磁鐵的電流中斷的交換機中,使交換開關(guān)不斷來回迅速切換迅速。這種機動逆變器式開關(guān),稱為一個振動器或蜂鳴器,曾經(jīng)在真空電子管汽車收音機中使用。一個類似的電子裝置已用于門鈴,蜂鳴器和紋身槍。當(dāng)開關(guān)管有有足夠的額定功率,晶體管和半導(dǎo)體開關(guān)各種其他類型的的電子開關(guān)器件可用已納入逆變器電路設(shè)計。</p><p><b>  3.2 輸出波形</b></p><p>

60、  上述簡單的逆變器中的開關(guān),當(dāng)不耦合到輸出變壓器時,輸出電壓波形由于開關(guān)管簡單的導(dǎo)通或關(guān)斷產(chǎn)生一個方波電壓輸出,而不是交流電最常見的正弦波形,它是一個AC電源波形通常由于其簡單。利用傅里葉分析,周期性波形表示為一個無窮級數(shù)的正弦波的總和。正弦波中和原始波形具有相同的頻率的波稱為基波。其他頻率的正弦波,稱為諧波,這是該系列中包括有頻率是基波頻率的整數(shù)倍。</p><p>  輸出波形是從一個逆變器所需的質(zhì)量取決于

61、逆變器所連接的負載特性。一些載入需要一個近乎完美的正弦波電壓供應(yīng)才能正常工作。其他的負載可能使用方波電壓也能工作的很好。</p><p>  3.3 三相逆變器</p><p>  三相逆變器是用于變頻驅(qū)動應(yīng)用以及諸如高壓直流輸電高功率傳輸。一個基本的三相逆變器由三個單相開關(guān)每個連接到三個負載接線端子之一的逆變器組成。對于最基本的控制方案,對三個開關(guān)運作協(xié)調(diào),以便在每一個開關(guān)輸出波形的基

62、本操作60度點。這將創(chuàng)建一個線到線輸出波形有六個步驟。六步之間有一個波形的方波的正面和負面的部分零電壓一步,這樣的諧波,是三個被淘汰上述倍數(shù)。當(dāng)載波脈沖調(diào)寬技術(shù)技術(shù)應(yīng)用到六步波形時,在整體上基本形狀,或著波形的包絡(luò)將被保留,以使三次諧波及其倍數(shù)被取消</p><p><b>  4 歷史</b></p><p>  4.1 早期的變頻器</p>&l

63、t;p>  從十九世紀(jì)晚期到二十世紀(jì)中葉直流到交流電源的轉(zhuǎn)換使用旋轉(zhuǎn)逆變器或者發(fā)電機組來完成。在二十世紀(jì)早期,真空電子管和充氣管開始被作為逆變電路開關(guān)使用。應(yīng)用最廣的電子管的類型是閘流管。</p><p>  機動電子逆變器一詞解釋了學(xué)術(shù)上逆變器的來源。早期的交流到直流轉(zhuǎn)換器使用的感應(yīng)或同步交流電動機直接連接到一臺發(fā)電機(發(fā)電機),使發(fā)電機的整流子扭轉(zhuǎn)在正確的時間來產(chǎn)生直流電。一個后來的發(fā)展是同步轉(zhuǎn)換器,其

64、中電機和發(fā)電機繞組組合成一個電樞,一個滑環(huán)在電樞一端,整流子在另一端,只有一幀。這樣的結(jié)果是交流輸入,直流輸出。隨著設(shè)置,直流電可以被認(rèn)為是分開的出現(xiàn)的交流電;具有同步轉(zhuǎn)換器,在一定意義上講,它可以被認(rèn)為是“機械糾正交流“。只要有了正確的輔助和控制設(shè)備,設(shè)置或旋轉(zhuǎn)轉(zhuǎn)換器可“向后跑“,轉(zhuǎn)換直流到交流。因此,逆變器是一個倒置的轉(zhuǎn)換器。</p><p>  4.2 整流逆變器控制</p><p&g

65、t;  自從1957年初以來晶體管沒有足夠的電壓和額定電流可用于大多數(shù)逆變器應(yīng)用,晶閘管或可控硅整流器的開始到固態(tài)逆變器電路過渡。</p><p>  晶閘管換相的條件是在可控硅電路設(shè)計中考慮的關(guān)鍵因素??煽毓璨魂P(guān)閉或整流時自動門控制信號被切斷。只有當(dāng)正向電流降至低于最低維持電流,他們才會關(guān)閉,通過外部加工,不同類型的晶閘管最低電流也會不同。對于連接到交流電源的可控硅,每一次整流源電壓極性都會自然反轉(zhuǎn)。連接到直流

66、電源的可控硅整流通常需要強迫轉(zhuǎn)換,迫使電流為零時,需要換一種途徑。最不復(fù)雜的電路采用可控硅整流自然代償,而不是強制。隨著附加的代償電路,可控硅已經(jīng)用于上述逆變器種類。</p><p>  在逆變電源將直流電轉(zhuǎn)換為交流電的應(yīng)用中,它可以使用交流到直流整流控制電路中的反演模式運行。在反轉(zhuǎn)模式,可控整流逆變電路工作作為換一條線。這種類型的操作,可用于高壓直流輸電系統(tǒng)和再生制動電機控制系統(tǒng)的操作。</p>

67、<p>  另一種類型的可控硅逆變電路是電流源輸入的逆變器。電流源輸入逆變器是一個雙重的六個步驟電壓源逆變器。用電流源逆變器,直流電源配置為電流源,而不是一個電壓源??煽毓枘孀兤髦星袚Q一個六步序電流指示作為加強電流波形三相交流負載。電流源輸入逆變器換相方法包括負載代償和并聯(lián)電容器代償。隨著這兩種方法,輸入電流調(diào)節(jié)輔助代償。負載換向,負載是一個同步電動機在運行領(lǐng)先的功率因數(shù)。由于他們已能夠為更高的電壓和額定電流使用,如晶體管或可

68、通過控制信號變成了絕緣柵雙極性晶體管的半導(dǎo)體手段已成為首選的開關(guān)逆變器電路中使用的組件。</p><p>  4.3 整流器和逆變器脈沖數(shù)</p><p>  整流電路通常是每周期的交流輸入電壓流入的直流側(cè)的直流幀數(shù)來分類。單相半波整流是一個脈沖電路和單相全波整流是雙脈沖電路。一個三相半波整流是三脈沖電路和三相全波整流是一個六脈沖電路。對于三相整流器,有整流器兩個或兩個以上,有時串聯(lián)或并

69、聯(lián)以獲得更高的電壓或電流額定值。整流器輸入,提供從供應(yīng)特種變壓器移相輸出。這具有倍增效應(yīng)階段。 6個階段分別從兩個變壓器,從十二相從三個變壓器等。相關(guān)的整流電路為12脈沖整流器,18脈沖整流器等。</p><p>  當(dāng)控制整流電路中的反向模式時,他們也按輸出脈沖數(shù)分類。整流電路具有較高的脈沖數(shù)減少在交流輸入電流,并減少直流輸出電壓紋波的諧波含量。在反向模式,電路具有較高的脈沖數(shù)有較低的交流輸出電壓波形的諧波含量

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