【2017年整理】基于ARM7的三相电机智能保护器设计.doc

基于ARM7的三相电机智能保护器设计 摘要 由于电网、负载及电机本身的种种原因使三相电机经常发生损坏现象，造成巨大经济损失，因此，电机的可靠保护就成了人们长期以来一直关注的问题。 本论文介绍了一种基于LPC2131的电机智能保护监测系统，提出了三相电机在发生漏电、断路、短路、缺相、堵转、电流不平衡等常见故障时的判据，并给出了硬件和软件设计思想。 其基本思想为采用电流互感器将电机转子中的电流感应出来，经过I/V变换，将电压信号送入AD进行采样，LPC2131对数据分析处理后进行相应动作。本保护器采用抽屉式结构，减小了体积；软件上采用交流采样，提高了测量的准确度，还能测量动态交流电量。与现有的电机保护器相比较，增加了一片实时时钟芯片，可以有效记录电机发生故障的时间，便于维修处理。而且本设计还可实时显示当前电机各相中的电流，相电压等。本保护器还增加了一个RS485通讯模块，可多台保护器挂在RS485总线上，由上位机进行控制。考虑到保护器工作的恶劣环境，我们在进行系统硬件和软件设计时均采取了许多必要的抗干扰措施，有效的提高了保护器的可靠性。 关键词　ARM7；故障监测；交流采样法；电机保护 The Design of Intelligent Protection and Control Instrument For Motor Based on ARM7 Abstract Due to the causes of power net、loads and itself, the three-phase motor often leads to damage. It brings great loss in economy. So the protection of motor is the issue which people pay close attention to for a long time. This thesis presents an intelligent monitoring protection system which is based on LPC2131 for use with motors as well as shows some breakdown judgements on the motor breakdown phenomena such as leak electricity of motor, the deficiency, the short circuit and imbalance of three phases current. The design idea on both hardware and software is also given. The elementary idea is that adopting current mutual inductance instruments induce current from motor’s rotors. Then send the current signal to I/V conversion circuit. The LPC2131’s A/D conversion will sampling the sine voltage signal. After calculating and analyzing the sampled data, the LPC2131 will act in correspondence. The protection instrument is designed as a kind of drawer structure, decreased its bulk. Moreover, this protection instrument can display current、voltage of the motor’s three-phase. We increase a RS485 communication module. Multi-instruments can hang over the RS485 bus. They are controlled by host computer. Considering the execrable environment the protection instrument worked, we adopt many indispensable anti_jamming measures when we design hardware and software of this system. These measures improve