蓄电池组均衡充电控制策略的研究

Research of Equalizing Charge Control Strategy for VRLA Batteries Circuit

独立光伏VRLA蓄电池储能系统是由多个单体电池串联而成,由于单体电池内阻、电压和容量的不一致,导致使用过程中差别扩大,使电池组循环寿命缩短。通过分析蓄电池不一致的原因,针对非耗散型均衡控制电路,深入研究电池组均衡充电控制的电路模型,并在此基础上提出了一种简单、高效、高可靠性的均衡充电控制方案。该方案中的PWM分流模块能自动实现单体电池间的能量转移,从而能逐步减小电池组的不一致性,它能保证电池组中所有电池单体在充电中后期都处在同一充电深度。实验结果表明,该电路能够实现电池单体间高效、快速的电压均衡,可有效避免电池单体过充和过放,大大延长了蓄电池的使用寿命。

In energy storage of stand-alone photovoltaic system,battery string with many cells in series connection can provide higher voltage.But for each cell,any slight voltage difference can be amplified in the charging and discharging cy-cles.Unbalanced cell voltage in battery string will give rise to serious over-charging or over-discharging,and decrease the total storage capacity and the battery cycle life.Therefore,maintaining cell voltage at an equal charge/discharge level is significant for enhancing the battery cycle life.Aiming at the non dissipative-type equalization circuits,the circuit model of battery equalization charge was studied,and an equalization charge control strategy which can not only achieves quick charge but also increases the battery cycle life was proposed.According to the proposed charge control strategy,a control-lable PWM divergence module can automatically realize energy transfer between cells and overcome dissimilarity among all batteries.Experiment shows that high energy transmission efficiency and rapid voltage equalization are achieved,and the battery overcharge or over discharge can be avoided and extend storage battery lifetime.