电工实验室恒流电子负载设计与实现

Design and implementation of a constant current electronic load for electric circuit laboratory

为提高电工实验室的利用效率及降低实验成本,设计了可调恒流电子负载。利用单片机的数字端口读入电流参考值和启停信号,用片上12位DAC生成负载电流控制器参考值;底层控制采用通用运算放大器实现了PID调节器,利用模拟电路实现了恒流与过压保护选择性控制。经测试,该电子负载较好地实现了恒流负载模式,并且具有过压保护、键盘输入、数字显示功能,功能完备、成本低,能满足电工实验室的使用要求。

In order to improve the operation efficiency of the electric circuit lab as well as to reduce the running cost, an adjustable constant current electronic load is proposed in this research. The current reference command and the start/stop Command are read from the digital I/0 of the micro-controller and translated into a voltage level issued by the DAC on chip; the local PID control is implemented in a general purpose operation amplifier, and an analog protection circuit is designed to toggle the operation modes between constant current and protective voltage control. The experimental results indicate well functionality of constant current control as well as over-voltage protection, keyboard input, digital display. The proposed system is suitable for electric circuit lab due to its good functionality and low cost design.