基于SOC变频飞度电容法的VFB能量均衡控制策略

Energy Balancing Strategy for Vanadium Redox Flow Battery Based on Variable Frequency Fit Capacitance Method

为解决全钒液流电池(VFB)组成材料差异、生产工艺误差和运行中电化学反应速率不一致等对电池容量、使用寿命、安全和转化效率带来的问题,提出基于SOC变频飞度电容法的VFB能量均衡控制策略。该策略以SOC为均衡判断依据,超级电容为能量转移元件,通过切换MOS管,改变MOS管的频率,实现电池间能量的平衡。同时,为降低开关管损耗和提高均衡效率,利用Simulink仿真对比定频率和变频率均衡的差异。仿真结果表明该策略可有效改善电池组间的能量平衡,提高系统的使用寿命。

Unstable materials composition,manufacturing deviation,and inconsistent electrochemical reaction rates of vanadium redox flow battery(VFB)usually cause problems in aspects of battery capacity,service life,battery safety,and conversion efficiency.In view of this an energy balancing strategy for VFB based on variable frequency fit capacitance method was proposed.The strategy takes SOC and supercapacitors as the basis for identify energy balance and energy transfer component,respectively,and achieve inter-battery energy balance through switching different MOS tubes and changing MOS frequency.Furthermore,in order to reduce switching tube loss and improve balancing efficiency,Simulink simulation was used to determine difference between frequency-consistent balancing and frequency-variable balancing.The proposed strategy was proved by simulation results efficient in improving inter-battery energy balance and extending battery service life.