Research On Electric Control Technology Of Micro-nano Satellite Battery Pack

The current design requirements of small size and light weight of micro-nano-satellites and the working characteristics of short orbital cycles and many charge/discharge cycles make the life of micro-nano-satellite systems constrained by the life of the power system,especially the battery pack.The study of reliable and efficient lithium-ion battery control technology is a top priority for today’s micro-nano-satellites.In this paper,three aspects of satellite lithium-ion battery pack charging and discharging control,battery charge state estimation and satellite lithium battery pack equalisation control are studied to achieve the objectives of improving satellite lithium-ion battery pack performance and utilisation,slowing down the rate of lithiumion battery pack loss and extending the service life of micro-nano-satellites.The main research work is as follows:(1)Analyzing the characteristics of the micro-nano satellite in orbit and the characteristics of Li-ion battery charging and discharging,designing a constant-current-constant-voltage charging control scheme based on Superbuck circuit and a boost-discharge control scheme to stabilize the bus voltage to achieve efficient control of Li-ion battery pack charging and discharging.(2)To address the problems of error accumulation in the estimation of SOC by the amperetime integration method commonly used in satellite Li-ion battery packs,an extended Kalman SOC estimation algorithm based on the simulated annealing algorithm is proposed to simplify the process of empirical trial and error debugging required for the extended Kalman algorithm in engineering applications and to improve the accuracy of SOC estimation.(3)To address the problems of heat loss,low efficiency and slow equalisation speed of the energy dissipation scheme mostly used for the equalisation control of satellite Li-ion battery packs,an active equalisation scheme based on mean-fuzzy control for double-layer boost converters is proposed.This scheme can improve the inconsistency between single cells more quickly and increase the efficiency of Li-battery pack capacity utilization and service life compared with the traditional single-layer equalization scheme and the double-layer equalization scheme without fuzzy control.A micro-nano satellite battery bank control simulation system has been constructed.The system is simulated under different operating conditions and proves that the charging and discharging control scheme and the equalisation control scheme with the SOC estimation result as the equalisation variable are feasible and meet the requirements of satellite power bus control and the control of the battery bank.