考虑不同容量的储能SOC均衡与功率分配策略

SOC Balancing and Power Distribution Strategies Considering Different Capacities of Energy Storage

孤立直流微电网通常需配置由分布式储能单元(distributed energy storage units,DESUs)组成的储能系统。为延长储能系统的使用寿命,其应保持DESUs的荷电状态(state of charge,SOC)处于均衡状态,但在实际应用中,DESUs的容量可能存在差异,线路电阻不匹配,严重影响SOC的均衡效果。针对此问题,提出一种改进的下垂控制策略,通过指数函数嵌套幂函数,增强了下垂系数对SOC变化的辨识度,从而提升SOC的均衡效果;其次,通过均衡功率状态因子,使DESUs的输出功率按容量成比例地分配。为减少通信压力,采用稀疏通信网络来传递各DESUs所需的信息,即运用动态一致性算法估计全局平均值。最后,基于MATLAB/Simulink搭建的仿真模型验证了所提策略的有效性。

Isolated DC microgrids should be equipped with energy storage systems consisting of distributed energy storage units.To extend the service life of the energy storage system,the latter should keep the charge state of distributed energy storage units(DESUs)in a balanced state;however,in practice,there may be differences in the capacity of DESUs and mismatch in line resistance,which seriously affect the balancing effect of state of charge(SOC).To address this issue,this study proposes an improved sag control strategy,which enhances the discrimination of the sag coefficient to SOC variations by nesting exponential functions with power functions,thus improving the equalization effect of the SOC.Next,by defining and equalizing the power state factor,the output power of DESUs is proportionally distributed according to their capacity.To reduce the communication pressure,this study adopts a sparse communication network to convey the required information of each DESUs,i.e.,the global average value is estimated by applying the dynamic consistency algorithm.Finally,a simulation model built on MATLAB/Simulink verifies the effectiveness of the proposed strategy.