【正文】 程：電池和充電主電源之間串聯(lián)繼電器J1的常開觸點(diǎn)J1，它閉合才能接通充電通路。 圖中BGD0R6D03組成+12V輔助電源，屬于前面講過的典型的穩(wěn)壓二極管D05的擴(kuò)流電路，還擔(dān)負(fù)著其他低壓控制電路的供電。無論何種電動(dòng)車充電器，主電源都連接電池，為了人身安全，與市電應(yīng)該是隔離的。但是相當(dāng)多的不經(jīng)穩(wěn)壓直接供應(yīng)TL494。* 充電電路接入被充電池時(shí)，發(fā)光二極管 LED2點(diǎn)亮，表示充電進(jìn)行中。3內(nèi)置誤差放大器。內(nèi)置功率晶體管可提供500mA的驅(qū)動(dòng)能力推或拉兩種輸出方式。當(dāng)雙穩(wěn)觸發(fā)器的時(shí)鐘信號(hào)為低電平時(shí)才會(huì)被選通，即只有在鋸齒波電壓大于控制信號(hào)期間才會(huì)被選通。當(dāng)把死區(qū)時(shí)間控制輸入端接上固定的電壓（范圍在0—）即能在輸出脈沖上產(chǎn)生附加的死區(qū)時(shí)間。誤差放大器的輸出端常處于高電平，它與脈沖寬度調(diào)制器的反相輸入端進(jìn)行“或”運(yùn)算，正是這種電路結(jié)構(gòu)，放大器只需最小的輸出即可支配控制回路。（2）開關(guān)管導(dǎo)通比由脈寬調(diào)制（PWM）電路決定，脈寬調(diào)制電路（PWM）是電壓比較器，有兩個(gè)輸入：一個(gè)是比較基準(zhǔn)—幅度恒定的鋸齒波（三角波），一個(gè)是浮動(dòng)的比較電壓—預(yù)設(shè)值和負(fù)反饋混合后的電壓。充電器PWM輸入的預(yù)設(shè)比較電壓一般有兩個(gè)：（1）限流充電階段，比較高；（2）涓流充電階段，比價(jià)低。 圖42 山東GD36半橋式充電器框圖工作原理和調(diào)試方法如下：1）性能指標(biāo)輸入電壓：170260V；輸出電壓：44V（可調(diào)）最大充電電流：；浮充電電流：200100mA2）電路原理充電器電路主要由市電整流濾波、自激加他激半橋轉(zhuǎn)換、PWM控制、電壓控制、電流控制、輸出整流濾波六部分組成。自激振蕩是利用磁芯和特性產(chǎn)生的，具體過程如下。與此同時(shí)，③⑤繞組感應(yīng)出③腳正、⑤腳負(fù)的電壓，使Q2截止。此后，這種過程重復(fù)進(jìn)行而形成振蕩。B3 的次級(jí)⑨⑦、⑨⑧繞組輸出電壓D15全波整流、C21濾波得到+44V電壓給蓄電流充電。這樣，一方面消除了反峰電壓，另一方面因反激能量回送電源而極大地提高了電源的效率。圖43 山東GD36半橋式充電器RR24分壓值設(shè)定死區(qū)控制④腳的電位。R3是電流取樣電阻，取樣電壓經(jīng)R13加到TL494的⒂腳進(jìn)行電流控制。D1D14的作用與DD7相似，保護(hù)4，把B2初級(jí)的反激能量回送電源。3)調(diào)試a. 輸出電壓開路輸出電壓為44V，改變R26或R27可校準(zhǔn)此值。改變R30可校準(zhǔn)該狀態(tài)。 這些充電器有些故障類同，例如空載有較低輸出電壓，帶負(fù)載輸出消失。更換零件后通知檢查，不帶負(fù)載，但要在市電輸入端串聯(lián)一只普通的100瓦白熾燈泡，開機(jī)時(shí)，若白熾燈泡閃亮一下變暗，同時(shí)半橋式充電器各種發(fā)光管正常發(fā)光，說明基本修好了，可以進(jìn)行其他項(xiàng)目了；如果白熾燈泡常亮不變暗，說明還有其他故障。因此，有示波器的，在換開關(guān)管后，用穩(wěn)壓電源給集成電路供電，模擬改變穩(wěn)壓反饋系統(tǒng)反饋電壓，用示波器觀察占空比是否有相應(yīng)變化。以12V電瓶為例，否則失水嚴(yán)重?；蛘叻催^來，減小取樣電阻下半部分電阻值，輸出電壓升高；增大取樣電阻下半部分電阻值，輸出電壓降低的方法。總 結(jié) 電動(dòng)自行車具有節(jié)能、安全、高品質(zhì)、污染小等優(yōu)點(diǎn)。為以后走向工作奠定了實(shí)踐基礎(chǔ)。大學(xué)生活即將結(jié)束，這一路走來，有時(shí)荊棘滿地步履維艱，有時(shí)又陽光明媚豁然開朗，我很感謝王宇炎老師在設(shè)計(jì)中的講解和幫助，伴我順利完成大學(xué)里最重要的畢業(yè)設(shè)計(jì)時(shí)光。在此我要感謝所有關(guān)心和愛護(hù)我的人。s latest NemicLambda launched a softswitch technology using highfrequency switching power supply module RM Series, the switches at (200 ~ 300) kHz, the power density has reached 27 W/cm3, using synchronous rectifier (MOS  FET replace SCHOTT Diode), the efficiency of the entire circuit to 90 percent. 2 AC/DC transform AC / DC transformation is to transform exchange for DC, its power can be a twoway flow, the flow of power flow from the power load known as the rectification, the power flow from the load to return to power as active inverter. AC / DC converter for the importation of AC 50/60 Hz, due to the rectification, filtering, the relatively large size of the filter capacitor is essential, because encountered safety standards (such as UL, CCEE) and EMC Directive Restrictions (such as IEC, FCC, CSA), AC input side and EMC filter must meet safety standards and the use of the ponents, such restrictions on the AC / DC power of the small size of the addition, since the internal highfrequency, highpressure, big Current switching action, made the resolution of EMC difficult to electromagnetic patibility problems, will install the internal highdensity circuit design to the high demand for the same reason, highvoltage, high current power switches make greater loss of work, limiting the AC / DC converter modular process, it must be in power system design methods to optimize the efficiency of its work reaches a certain level of satisfaction. AC / DC transform the circuit can be divided into the connection mode, halfwave circuit, fullwave circuit. By the power of a few can be divided into, singlephase, threephase, multiphase. Circuit work on a quadrant can be divided into quadrants, the quadrant, the threequadrant, the four quadrants. Selection of switching power supply 3 Switching power supply In the importation of antijamming performance, as its own circuit of the characteristics of (multilevel series), the general importation of interference such as a surge through the difficult, in the output voltage stability of the technology indicators pared with the linear power Have greater advantages, its output voltage stability up ( to 1)%. Switching power modules as a power electronic device integration, the choice should note the following: Because of the high efficiency switching power supply, can usually more than 80 percent, it was their choice of output current, accurate measurement of electrical equipment or calculating the maximum absorption current, so that was the choice of switching power supply has a high cost performance, Output is usually calculated as follows: Is = KIf Type in: Isswitching power supply is rated output current。s switch to accelerate the pace of development of power industry, we must walk the road of technological innovation, out of production, study and research with Chinese characteristics, the joint development, for the rapid development of China39。隨著電力電子技術(shù)的發(fā)展和創(chuàng)新，使得開關(guān)電源技術(shù)也在不斷地創(chuàng)新，這一成本反轉(zhuǎn)點(diǎn)日益向低輸出電力端移動(dòng)，這為開關(guān)電源提供了廣闊的發(fā)展空間。開關(guān)電源可分為AC/DC和DC/DC兩大類，DC/DC變換器現(xiàn)已實(shí)現(xiàn)模塊化，且設(shè)計(jì)技術(shù)及生產(chǎn)工藝在國內(nèi)外均已成熟和標(biāo)準(zhǔn)化，并已得到用戶的認(rèn)可，但AC/DC的模塊化，因其自身的特性使得在模塊化的進(jìn)程中，遇到較為復(fù)雜的技術(shù)和工藝制造問題。其具體的電路由以下幾類： （1）Buck電路——降壓斬波器，其輸出平均電壓U0小于輸入電壓Ui，極性相同。當(dāng)今軟開關(guān)技術(shù)使得DC/DC發(fā)生了質(zhì)的飛躍，美國VICOR公司設(shè)計(jì)制造的多種ECI軟開關(guān)DC/DC變換器，其最大輸出功率有300W、600W、800W等，相應(yīng)的功率密度為(、17)W/cm3，效率為（80～90）％。AC/DC變換按電路的接線方式可分為，半波電路、全波電路。開關(guān)電源模塊作為一種電力電子集成器件，在選用中應(yīng)注意以下幾點(diǎn)：因開關(guān)電源工作效率高，一般可達(dá)到80％以上，故在其輸出電流的選擇上，應(yīng)準(zhǔn)確測(cè)量或計(jì)算用電設(shè)備的最大吸收電流，以使被選用的開關(guān)電源具有高的性能價(jià)格比，通常輸出計(jì)算公式為： Is=KIf式中：Is—開關(guān)電源的額定輸出電流； If—用電設(shè)備的最大吸收電流； K—裕量系數(shù)，～； 開關(guān)電源比線性電源會(huì)產(chǎn)生更多的干擾，對(duì)共模干擾敏感的用電設(shè)備，應(yīng)采取接地和屏蔽措施，按ICE1000、EN61000、FCC等EMC限制，開關(guān)電源均采取EMC電磁兼容措施，因此開關(guān)電源一般應(yīng)帶有EMC電磁兼容濾波器。由于開關(guān)電源輕、小、薄的關(guān)鍵技術(shù)是高頻化，因此國外各大開關(guān)電源制造商都致力于同步開發(fā)新型高智能化的元器件，特別是改善二次整流器件的損耗，并在功率鐵氧體（MnZn)材料上加大科技創(chuàng)新，以提高在高頻率和較大磁通密度（Bs)下獲得高的磁性能，而電容器的小型化也是一項(xiàng)關(guān)鍵技術(shù)。模塊化是開關(guān)電源發(fā)展的總體趨勢(shì)，可以采用模塊化電源組成分布式電源系統(tǒng)，可以設(shè)計(jì)成N＋1冗余電源系統(tǒng)，并實(shí)現(xiàn)并聯(lián)方式的容量擴(kuò)展。g an employment tribunal claiEmployment tribunals sort out disagreements between employers and employees.You may need to make a claim to an employment tribunal if:Dismissal.You can make a claim to an employment tribunal, even if you haven39。Further help.Employment tribunals are less formal than some other courts, but it is still a legal process and you will need to give evidence under an oath or affirmation.Most people find making a claim to an employment tribunal challenging. If you are thinking about making a claim to an employment tribunal, you should get help straight away from one of the organisations listed underif you win the case.If you are thinking about signing up for 16