基于单片机的电子负载毕业论文(含原理图+程序).docx

学海无涯苦作舟! 学海无涯苦作舟! 电子负载的原理是控制内功率 MOSFE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 MOSFE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，MOST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 电子负载的电流恒定，实现恒流工作模式。 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调节器；AD转换；DA转换 ABSTRACT The prin ciple of electro nic load is con trol of tran sistors in side power MOSFET or the guide flux of power tube, it is a consumption power equipment which depends on the dissipation power of tube, there are four basic working ways that persistenee pressure, con sta nt curre nt, the con sta nt resista nee, con sta nt power . This desig n start with the an alysis of DC electric load system soluti on s, it discussed the realization of the whole system hardware circuit and software in detail, and give a reas on able soluti on. In order to realize the con trol and the expa nsion of fun ctio n conveniently, we adopted the STC89C52 microcontroller as the core controller, and desig ned the DA output con trol circuit, AD voltage curre nt detect ion circuit, keyboard circuit, display circuit and drive circuit, through the coord in ati on betwee n hardware and software, fin ally, we realized the whole desig n. PI adjuster and n egative feedback con trol loop of the circuit which control the grid voltage of MOSFET, so as to change its resista nee. The core esse nces are the op-amp, MOS tube here both as a con trol device and as a power load tested. Con trolli ng the guide flux of the MOS tube, the resista nee of the MOS tube will cha nge accordi ngly, thus the curre nt which flows the electro nic load curre nt will con sta nt, At last, we realized con sta nt curre nt work pattern. This design can realize the Constant-current control of the electronic loa