基于STM32的直流电子负载设计

Design of DC electronic load based on STM32

针对传统负载控制精度不高、分立阻值不连续等问题,设计了一种基于STM32F103C8T6单片机的直流电子负载。在单片机外围采用18位DA转换器对负载电压和回路电流高精度测量,内部采用增量式PID算法,通过调整工作在线性区的MOSFET上的负载电流,实现定电阻、定电流和定功率3种工作模式,并具有CAN通信功能有利于电子负载模块化。研究设计了MOSFET门极驱动电路,利用PI滤波器消除MOSFET寄生电容的自激振荡。根据该设计搭建的实验平台,经过不断的测试和优化,具有较高的稳定性和精度,已经用于蓄电池的性能测试和老化实验。

As for the problems of traditional load like low accuracy and discrete resistance, a DC electronic load based on STM32 F103 C8 T6 MCU is designed. The periphery of MCU uses 18-bit D/A converter for the high-precision measurement of the load voltage and loop current, and its interior uses incremental PID control algorithm in this paper. The MOSFET load current in linear region is controlled to realize constant current, constant resistance, constant power mode. CAN communication function that is beneficial to the modularization of the electronic load is also designed. A circuit to drive MOSFET gate is proposed in this paper, and self-oscillation produced by MOSFET stray capacitance is eliminated by the PI filter. Moreover, the relative experimental platform has been made out, which has been tested and optimized. The practice test proves that the proposed electronic load possesses high stability and precision, which has been be applied to the performance testing and aging experiments of battery.