考虑超级电容SOC的混合储能系统功率分配策略

Power Allocation Strategy of Hybrid Energy Storage System Considering Supercapacitor SOC

为解决超级电容能量密度小、在运行过程中荷电状态(state of charge,SOC)容易越限的问题,对传统低通滤波法进行改进,提出考虑超级电容SOC的功率分配策略。该方法依据超级电容的SOC划分5个不同的工作区域,并以超级电容的SOC作为变量,在不同工作区域同滤波时间常数建立相应的函数关系,之后根据SOC的变化动态调整滤波时间常数,实现蓄电池和超级电容之间功率的合理分配,保证超级电容SOC维持在合理范围内。最后,在Matlab/Simulink中搭建相关模型并仿真验证所提方案的正确性和有效性。仿真结果表明,同传统低通滤波法相比,该方法可在平抑功率波动的同时,根据超级电容的SOC合理分配超级电容和蓄电池的功率需求,使超级电容的SOC自行恢复,防止其过充过放,提高了直流微电网系统运行的经济性和稳定性。

In order to solve the problem that the energy density of supercapacitors is small and the state of charge(SOC)is easy to exceed the limit during operation,this paper improves the traditional low-pass filtering method and proposes a power allocation strategy considering the SOC of supercapacitors.The method divides five different working areas according to the supercapacitor SOC,and takes the supercapacitor SOC as the variable,establishes the corresponding functional relationship with the filter time constant in the different working areas,and then dynamically adjusts the filter time constant according to the SOC change,so as to realize the reasonable distribution of power between the battery and the supercapacitor,and ensure that the supercapacitor SOC is maintained in a reasonable range.Finally,the relevant model is built in Matlab/Simulink and the correctness and effectiveness of the proposed scheme is verified by simulation.The simulation results show that,compared with the traditional low-pass filtering method,this method can reasonably allocate the power demand of the supercapacitor and the battery according to the supercapacitor SOC while stabilizing the power fluctuation,so that the supercapacitor SOC can recover itself,prevent its overcharge and over discharge,and improve the economy and stability of the DC microgrid system operation.