Abstract:To address the issues of fixed control methods and limited adjustable parameters in traditional lithium battery charge-discharge systems, a modular charge-discharge system based on ARM is designed. The system adopts a "power module + ARM intelligent control" architecture, featuring a synchronous Buck-Boost converter for the charging circuit and a linear constant-current electronic load based on an operational amplifier and power MOSFET for the discharging circuit. With STM32F103C8T6 as the main controller, continuous regulation of charging voltage and current is achieved through PWM-to-analog conversion via GP8101. Remote configuration of the discharge module and a reserved interface for multi-module cascaded expansion are realized through the RS485/RS422 bus, and a touch screen is provided for human-machine interaction. Experimental results show that the output voltage deviation during charging and discharging is less than 0.5%, and the current control error is better than ±0.3%. Under 0.5C, 1.0C, and 1.4C rates, the discharge current fluctuations are less than ±0.02A, ±0.04A, and ±0.05A, respectively, while the charging current fluctuations are less than ±0.02A, ±0.05A, and ±0.05A, respectively. The system demonstrates stable constant-current charge-discharge performance across the full range, providing a low-cost, high-precision engineering solution for small-to-medium-scale battery testing in laboratory settings.
