移动通信开关电源的新技术及其应用电气工程及其自动化毕业论文中英文翻译

1、Mobile communication switching power supply new technology and its applicationABSTRACTThis article introduce the new technology and its practical application which at present moves which in the communications network to use the switching power supply uses, understood and grasped these new technologi

2、es has theimportant practical significance to the maintenance of equipment andthe engineering construction.Key word:switching power supply ;new technology; application.Foreword20 kHz switching power supply in overseas starts from the 70sto appear, to present switching power supply already in do main

3、 wide spread application and so on computer, corre spondence, domestic electric appliances. Along with the integrated circuit, the powerswitch component development, the switching power supply experienced from the separative element to the integration, from has compared the low frequency to compare

4、the high-frequency, since childhood the capacity to the large capacity process. The switching power supply technology also conforms to simplicity only develops complex and thetrend is mature. Because the power source is in the heart in the communications system the status, therefore communications s

5、ystem to high frequency switching power supply each target request all extremely strict, especially to the power factor, the constant voltage precision, the noise voltage and the efficiency request is very high.Therefore may say in the communications system uses the high frequency switching power su

6、pply has represented the switching power supply over all profession level, also has represented the switching power supply newest technology. At present the Jiangsu Province mobile communication equipment mainly uses American LORAIN, Hangzhou exhibitsones power (center is permanent), the Beijing con

7、certed effortlink, Wuhan 517 and so on the factory high frequency switching powersupply product, may divide into +27V and the -48V two kind of seriesaccording to the output voltage value.These factories products although in seemingly difference bigger, but all has used some same or the similar new t

8、echnology, therefore the product quality and the performance index relative are better. Underunifies several kind of switching power supplies which the Jiangsu Province mobile communication equipment uses, summarizes introduced ,now in the high frequency switching power supply uses some new technolo

9、gies as well as use these new technical the reason and its thepractical significance. Uses the new power switch componentStarts from the 90s intermediate stages, the power switchcomponent development obtains the rapid development, the high voltage,the big electric current, leads passes the resistanc

10、e small powerswitch component gradually to develop. Because is oxidizes the objectfield effect tube (MOSFET) to have the switching time to be short (10ns). The grid-driving power small (voltage drive component), to the tempera ture insensitive, does not have two time penetrates, the switch loses the

11、 merit which low, the pulse trailing electric current issmall also easy parallel to use, has substituted for the tradition aldouble pole transistor in the switching power supply to become the newpower switch component. At present the MVOS power metal oxidizes the object field effect tube turn-on fre

12、quency to be possible to achieve 450 MHz, already widely to frequency higher switching power supply,but ordinary VMOS tube when high voltage big electric current work leads passes the resistance to be very big, the component gives off heat, the output efficiency drops. Recent years developed the IGB

13、T insulation grid double pole transistornot only had the MOSryT voltage drive and so on all merits, meanwhile had the double-pole big power tube to saturated to lead passes the pressure drop low characteristic, mainly used in the hectowatt levelto the kilowatt level capacity frequency is about in th

14、e 2kkkHz switching power supply. According to the daily maintenance and the maintenance work statistics, in several kind of factories switching power supply modules which Jiangsu Province used uses the IGBT insulation grid double pole transistor to take the power switch component. Uses the power fac

15、tor compensation electric circuit.The power factor in the electrical power system is a count for muchtarget, the power group number (Pf) the definition changes suddenly the active power for the electrical network in and the load ratio of apparent power which or the pulsating current produces, in the

16、 ideal situation the power factor is 1. Creates the power factor small main reason is the alternating voltage and the electric current work(flows voltage and electric current in the different phase has phase-shift) or the alternating voltage and the electric current profile has the distortion. In th

17、e high frequency switching power supply mainly is because the power source input end rectification filter circuit is the accommodating load, causes the alternating voltage and the electric current has the phase deviation to cause thepower factor reduction. Moreover, because in electric circuit other

18、factors influences, also can cause the alternating current which the switching power supply inputs to have some distortions. Below thepower factor young fellow produces to the electrical power systemaffects: (1) causes the electrical network input alternating current toincrease. With I expression in

19、put current, i expression wattfulcurrent, obtains through the computation: When Pf=1.00,I=1.00i;Pf=0.92,I=1.09i;Pf=0.75, I=1.45i. Therefore in the load same situation, a power factor smaller electrical network input salternating current bigger, simultaneously the ring circuit loses increases, the el

20、ectrical network power supply efficiency reduces (2)to cause the electrical network neutral electric current to increase,the line harmonic interference is serious. Take the star connection as the example, L expresses the neutral electric current,when Pf=1.00, Ia, Ib, the Ic current waveform is a sin

21、e wave, also phase difference 120, after profile superimposition, And is causing the profile is the sine wave as far as possible,reduces the wave distortion, thus causes the exchange input the powergroup number to be approximate is 1. The power factor compensation electric circuit may divide into th

22、e active compensating circuit andthe passive compensating circuit two kinds, at present various factories widely use are the active power factor compensation electric circuit, this electric circuit core part is American Unitrode Corporations UC3854, through compensates may enhance the power factorto

23、 0.99 above, the input alternating current is the sine profile,enable the switching power supply module work to approach the pureresistance condition, meanwhile has the pre- constant voltage function.Uses the pulse width modulation (PWM) the soft switchtechnology - zero potential transformation (ZVS

24、) the electriccircuitAt present the high frequency switching power supply power transformation unit selects the pulse width modulation method, alsosome factories select the frequency modulation method. The arteriesdecide the modulation the basic principle are the adjustment square-wave occupy throug

25、h the adjustment pulse square-wave widthempty compared to, after causes the pulse square-wave rectificationfilter the direct component to change, achieves the output constantvoltage the goal, but the pulse square-wave frequency maintenance isinvariable. After the supposition switching power supply r

26、ectificationfilter voltage is U, L is the transformer primary coil, K1, K2, K3, K4 equivalent are four powers switching valves. When usesthe usual pulse-duration modulation technology, when K1, K2 leadpasses, when K3, K4 have cut off, the L beginnings and ends voltage isVL; When K1, the K2 closure,

27、K3, K4 lead passes, the L beginnings andends voltage is VL. Automatically uses the output current to flow the technologyBecause the communications system cannot interrupted move theparticularity, requests the power equipment work in the potentialbackup way,simultaneously because the communication fa

28、cility power is big,is also big to the power source output current capacity request,therefore the communication facility uses the switching power supply uses various modules parallel output beginning. This requests when various modules parallel work the output current must be same, equally shares to

29、 the load, and when in the system the module increases or thereduction, in the system works various modules can automatically redistribute the output current, realizes the N+n module hot backup. At present various factories use automatically flow the technicalrealization way to be various, but the p

30、rinciple all is carries on thesampling comparison to in the system module output current, then quitebad will control various modules the output voltage size, will bringin adjusts various modules the output current, will realize duringvarious modules to flow the work. The same precision sampling flow

31、sthe electric circuit to be possible to cause during various modules toflow the error to be smaller than positive and negative 3%, greatlyenhanced the system reliability.Above introduced in the mobile communication system use high frequency switching power supply uses some new technologies, in these

32、 powerequipment besides have used above introduces the technology, but alsohas used battery charging voltage temperature compensation, theopening machine slow start, the long-distance digit dialingmonitoring, the breakdown automatic detection and so on the new technology, these new technical uses, e

33、nable the high frequencyswitching power supply each performance index all to have a largerscale enhancement, causes the high frequency switching power supply tobe more and more stable. At present in some high frequency switching power supply product alsohas used renewal the and so on frequency modul

34、ation, monolithicintegrated circuit control technology, these technical uses will beable to cause the high frequency switching power supply maturer andare perfect, understood, will track and grasps these new technologiesto be able constructs the bigger instruction function to our lineservice and the

35、 engineering design.移动通信开关电源的新技术及其应用摘 要本文介绍了目前移动通信网中使用的开关电源所采用的新技术和其实际应用，了解和掌握这些新技术对设备维护和工程建设均具有重要的现实意义。关键词：开关电源；新技术；应用。 前 言20 kHz开关电源从70年代在国外开始出现，到现在开关电源已在计算机、通信、家用电器等领域广泛应用。随着集成电路、功率开关器件的发展，开关电源经历了从分离元件到集成化、从较低频率到较高频率、从小容量到大容量的过程。开关电源技术也从简单发展到复杂并趋向成熟。 由于电源在通信系统中处于心脏的地位，因此通信系统对高频开关电源的各项指标要求都非常严格，尤其

36、对功率因数、稳压精度、杂音电压及效率的要求很高。所以可以说通信系统中使用的高频开关电源代表了开关电源整体行业的水平，也代表了开关电源的最新技术。 目前江苏省移动通信设备主要使用美国LORAIN、杭州施威特克（中恒）、北京通力环、武汉517等厂家的高频开关电源产品，根据输出电压值可分为+27V和-48V两种系列。这些厂家的产品虽然在外观上差异较大，但都采用了一些相同或类似的新技术，因此产品质量和性能指标相对较好。下面结合江苏省移动通信设备使用的几种开关电源，概括介绍当今高频开关电源中采用的一些新技术以及采用这些新技术的原因及其实用意义。 使用新的功率开关器件从90年代中期开始，功率开关器件的研制

37、取得飞速发展，高电压、大电流、导通电阻小的功率开关器件逐步研制出来。由于属氧化物场效应管（MOSFET ）具有开关时间短（10ns）。激励功率小（电压激励器件）、对温度不敏感、无二次击穿、开关损耗低、脉冲拖尾电流小且易于并联使用的优点，在开关电源中已取代了传统双极型晶体管而成为新的功率开关器件。目前MVOS功率金属氧化物场效应管开关频率可达到 450 MHz，已广泛于频率较高的开关电源，但普通VMOS管在高电压大电流工作时导通电阻很大，器件发热，输出效率下降。近年研制出的IGBT绝缘栅双极型晶体管不仅具有MOSryT电压激励等所有优点，同时还具有双极大功率管正向饱和导通压降低的特性，主要用于百

38、瓦级到千瓦级容量频率为2kkkHz左右的开关电源中。根据日常的维护和维修工作统计，江苏省使用的几种厂家的开关电源模块中均采用了IGBT绝缘栅双极型晶体管作为功率开关器件。 采用功率因数补偿电路功率因数在电源系统中是一项非常重要的指标，功率因数(Pf)的定义为电网中突变或脉动电流产生的有功功率和负载的视在功率之比，理想情况下功率因数为1。造成功率因数小的主要原因是交流电压和电流工作在不同的相位（即交流电压和电流产生相移）或交流电压和电流的波形产生失真。在高频开关电源中主要是由于电源输入端的整流滤波电路是容性负载，使交流电压和电流产生相位偏移而使功率因数减少。另外，由于电路中其他因素的影响，也会使开关电源输入的交流电流产生一些失真。 功率因数小将对