面向光伏平抑考虑SOH与SOC的电池储能系统功率分配方法

POWER DISTRIBUTION METHOD OF BATTERY ENERGY STORAGE SYSTEM FOR PHOTOVOLTAIC POWER SUPPRESSION CONSIDERING SOH AND SOC

针对电池储能系统(BESS)参与光伏平抑时寿命损耗较高的问题,提出面向光伏平抑考虑健康状态(SOH)与荷电状态(SOC)的BESS功率分配方法。首先,将光伏并网标准、BESS容量和最大充放电功率作为约束条件,建立以并网波动率、BESS寿命损耗和SOC恢复为目标的光伏并网指令优化模型,并利用改进天鹰优化的改进雨流计数法进行求解;然后,设计BESS两级功率分配策略,在传统容量二分法的基础上引入离群组,并动态调整电池组容量,提出兼顾SOH和SOC的BESS动态分组方法,实现功率指令从BESS向电池组的初级分配,并进一步结合电池单元SOH与SOC的标准差与极差动态估计各电池单元响应能力,设计基于SOH/SOC均衡原则的电池单元功率分配方法,实现功率指令从电池组向电池单元的次级分配;最后,电池单元响应功率指令完成调节。采用某配备BESS的光伏电站的冬季典型日出力进行仿真验证,并与其他多种方案进行对比,结果表明,所提方法在满足光伏并网波动率的要求下,降低了电池SOH差异,增强了电池单元SOC一致性,减少了BESS寿命损耗。

To solve the issue of high life loss when the battery energy storage system(BESS)participates in photovoltaic power suppression,a power distribution method of BESS for photovoltaic power suppression considering state of health(SOH)and state of charge(SOC)is proposed.Firstly,the PV grid-connected standard,BESS capacity and maximum charge-discharge power are taken as the constraint conditions,and an optimization model of photovoltaic grid-connected signal is established with the objectives of gridconnected fluctuation rate,BESS life loss and SOC recovery.It is solved by the improved rain flow counting method optimized by improved aquila optimization algorithm.Then,a two-stage power allocation strategy of BESS is designed.Based on the traditional capacity dichotomy,exception group are introduced,and the capacity of the battery pack is dynamically adjusted.A BESS dynamic grouping method that takes into account both SOH and SOC is proposed,which is to realize the primary allocation of power instructions from BESS to the battery pack.Furthermore,the response ability of each battery cell is dynamically estimated by combining the standard deviation and range of SOH and SOC of the battery cell.The battery cell power distribution method based on SOH/SOC balance principle is designed to realize the secondary distribution of power command from battery pack to battery cell.Finally,the battery unit completes the adjustment in response to the power command.The typical daily output of a PV station equipped with BESS are used for simulation verification.Compared with other schemes,the results show that the proposed method reduces the SOH difference between battery groups,enhances the SOC consistency among battery units,and reduces the life loss of BESS with the satisfaction of the requirement of photovoltaic grid-connected fluctuation rate.