Power off Punctuality and Lithium Battery Pack Equalization Method based on STM32+AD7280A

Abstract

In view of the application of current equipment in Beidou satellite and other aerospace fields, a power-off punctual system with STM32F103 and AD7280A as the core was designed. When the main power supply was cut off, the lithium battery pack continued to supply power and ensured that the output remained stable during the switching process. Used LTC4359 and MOSFET to build switching circuit, realized stable switching of power supply-battery, battery-power input and make system anti-backflow. The AD7280A was used to collect each lithium-ion battery voltage and temperature and the current sampling circuit was used to accurately measure the battery parameters. Based on this, the battery voltage was used as the equilibrium criterion to achieve battery equalization; and combining open circuit voltage (OCV) method with ampere-hour integral method for SOC initial value correction and estimation. The experiment proves that the system achieves stable switching, the equalization error is less than 50mV, and the SOC estimation error is less than 2.3%.