程控直流电子负载设计VIP免费

本科生毕业设计（论文）I摘要电子负载的原理是控制内功率MOSFET或晶体管的导通量，靠功率管的耗散功率消耗电能的设备，它的基本工作方式有恒压、恒流、恒阻、恒功率这几种。本设计从直流电子负载系统方案分析入手，详细讨论了整个系统的硬件电路和软件实现，并给出较为合理的解决方案。为便于控制的实现和功能的扩展，采用了STC89C52单片机作为核心控制器，设计了DA输出控制电路、AD电压电流检测电路、键盘电路、显示电路和驱动电路，通过软、硬件的协调配合，实现了整个设计。通过运放、PI调节器及负反馈控制环路来控制MOSFET的栅极电压，从而达到其内阻变化。这个控制环路是整个电路的核心实质，MOS管在这里既作为电流的控制器件同时也作为被测电源的负载。控制MOS管的导通量，其内阻发生相应的变化，从而达到流过该电子负载的电流等恒定，从而实现四种工作模式。本设计能实现电子负载的恒流控制：能够检测被测电源的电流、电压及功率并由液晶显示。在额定使用环境下,恒流方式时不论输入电压如何变化（在一定范围内），电子负载将根据设定值来吸收电流，流过该电子负载的电流恒定。关键词：电子负载；恒流模式；PI调节；单片机控制本科生毕业设计（论文）IIAbstractTheprincipleofelectronicloadiswithinthecontrolofthepowerMOSFETortransistorconductionflux,thepowerdissipatedbythepowertubepowerconsumptionofthedevice,anditsbasicoperatingmodeandconstantvoltage,constantcurrent,constantresistance,constantpowerthesetypes.ThedesignofsystemsolutionsfromaDCelectronicloadanalysis,adetaileddiscussionoftheentiresystemhardwareandsoftware,andgivesamorereasonablesolution.Inordertofacilitatetheimplementationandcontroloftheexpansion,usingSTC89C52microcontrollerasthecorecontrollerdesignedDAoutputcontrolcircuit,ADvoltageandcurrentdetectioncircuit,keyboardcircuit,displaycircuitanddrivercircuit,throughsoftwareandhardwarecoordinationtoachievetheentiredesign.Bytheopamp,PIregulatorsandnegativefeedbackcontrollooptocontroltheMOSFETgatevoltage,soastochangeitsresistance.Thiscontrolloopisthecoresubstanceofthecircuit,MOStubeherebothasacurrentcontroldevicealsoservesasthepowersupplyundertestload.ControlMOStransistorconductionflux,itsresistancechangesaccordingly,soastoflowthroughtheelectronicloadcurrentisconstant,toachieveconstantcurrentmode.Thisdesigncanachieveconstantcurrentelectronicloadcontrol:theabilitytodetectthemeasuredsupplycurrent,voltageandpowerbytheLCD.Theratedusageenvironment,theconstantcurrentmoderegardlessoftheinputvoltagechanges(inacertainrange),theelectronicloadtoabsorbthecurrentaccordingtothesetvalue,theflowthroughtheconstantcurrentelectronicload.Keywords:electronicload;constant-currentpattern;PIregulator;SCMcontrol本科生毕业设计（论文）III目录第1章绪论....................................................................................................................11.1课题背景与意义...............................................................................................11.2直流电子负载的应用现状...............................................................................11.3直流电子负载发展现状...................................................................................21.4系统设计要求...................................................................................................3第2章方案论证............................................................................................................52.1电子负载的工作原理.......................................................................................52.2总体设计方案论证.....................................