准谐振式开关电源的设计

I准谐振式开关电源的设计摘要随着电力电子技术的发展，电力电子设备与人们的工作、生活的关系日益密切，而电子设备都离不开可靠的电源。开关电源产品广泛应用于工业自动化控制、特殊用途设备、仪器仪表、半导体制冷制热等领域。目前，开关电源以小型、轻量和高效率的特点被广泛应用于电子设备，是当今电子信息产业不可缺少的一种电源方式。目前由于开关电源频率的提高，需要减少开关损耗。谐振电路，以使开关上的电压或通过开关的电流呈正弦波，在减少开关损耗的同时也可控制浪涌的发生，这种方式的开关电源称为谐振式开关电源。准谐振开关电源使开关电源的可靠性、纹波干扰等问题得到很大改善，材料成本不增加而体积、重量却可以大大减少。除此之外，谐振式开关电源电路还可以克服PWM方式对负载的瞬态响应较差和易辐射等缺点，利用高频驱动的作用，降低损耗，提高效率，减少噪声。其中，部分谐振方式，将会成为主流技术。部分谐振转换电路技术，在理论上即可实现高频化又可降低噪声，但部分谐振转换技术的实际应用仍存在着技术问题，故仍需在这一领域开展大量的工作，以使得该项技术得以实用化。本文叙述了准谐振式开关电源的设计过程，描述了主电路的参数计算、器件的选择，介绍了NCP1207芯片实现准谐振控制的电路完整形式，实现了退磁检测、过流保护、过压保护、电压反馈。关键字：准谐振，开关电源，反激式，NCP1207IIQuasi-resonantswitchingpowersupplydesignAbstractWiththedevelopmentofpowerelectronics,powerelectronicsequipmentbecongmemoreandmoreImportantforus,electronicdevicescannotdowithoutreliablepower.Switchingpowersupplyproductsarewidelyusedinindustrialautomationandcontrol,specialpurposeequipment,instrumentation,semiconductorrefrigerationandheatandsoon.Atpresent,switchingpowersupplytosmall,lightweightandhighefficiencycharacteristicsarewidelyusedinelectronicequipment,anditisnotalackofpowermeans.Atpresent,becauseoftheincreasedfrequency,switchingpowersupplyneedstoreduceswitchinglosses.Resonantcircuit,inordertoswitchthevoltageorcurrentthroughtheswitchwasasinewave,reducestheswitchinglossesandalsocontrolthesurgeinplace.Thisapproachiscalledresonantswitchingpowersupply.Quasi-resonantswitchingpowersupplymakeproblemsuchasswitchpowersourcereliability,lineswaveinterferencegotverybigimprovement,anddoesnotincreasecostandreducethevolumeandweight.Inaddition,theresonantswitchingpowersupplycanovercomethepoortransientresponseandeasyradiationdefectsofPWMmodetoload,anduseofhigh-frequencydrivers,reducinglosses,improveefficiency,reducenoise.Partoftheresonantwillbecomemainstreamtechnology.Partoftheresonantconvertercircuittechnology,intheory,butalsocanreducethenoiseofthehighfrequency,butsomeofthepracticalapplicationofresonantconversiontechnology,therearestilltechnicalproblems,itstillrequiredmuchworkinthisareainordertomakethetechnologytopracticaluse.Thispaperdescribesthequasi-resonantswitchingpowersupplydesignprocess,describethemaincircuitparametercalculation,thedeviceofchoice,introducedtheNCP1207chipquasi-resonantcontrolcircuitcompletetheformandrealizedthedemagnetizationdetection,over-currentprotection,over-voltageprotection,voltagefeedback.Keywords:quasi-resonant,switchingpowersupply,flyback,NCP1207III目录摘要............................................................................................................................................IAbstract..................................................................................................................................II第1章绪论............................................................................................................................11.1准谐振开关电源的概述...............................................................................................11.1.1开关电源的发展.................................................................................................11.1.2准谐振开关电源的优点[3]..................................................................................21.1.3准谐振开关电源的缺点[3]..................................................................................31.2设计要求......................................................................................................................31.3完成设计方案..............................................................................................................41.3.1DC-DC主回路拓扑.............................................................................................41.3.2控制方法及实现方案.........................................................................................41.3.3提高效率的方法及实现方案..............................................................................4第2章主电路设计....................................................................................................................52.1准谐振开关电源的基本原理[4]....................................................................................52.2输入电路......................................................................................................................72.2.1输入电路的选择.................................................................................................72.2.2主要参数计算.....................................................................................................72.3变换电路......................................................................................................................92.3.1变压器设计.........................................................................................................92.2.2开关管选用.......................................................................................................142.2.3谐振电容..........................................................................................................142.4缓冲电路.....................................................................................................................152.4.1缓冲电路原理............................................