考虑SOC的混合储能功率分配与自适应虚拟惯性控制

Hybrid energy storage power distribution and adaptive virtual inertia control considering SOC

电力电子化的直流配电网存在低惯性问题,不利于系统稳定运行。混合储能设备可向电网提供虚拟惯性,但不同类型的储能之间存在功率协调问题,并且储能的荷电状态(state of charge, SOC)对虚拟惯性的调节也有约束作用。针对上述问题,提出了一种自适应时间常数的分频控制策略,时间常数根据混合储能系统(hybridenergy storage system, HESS)的SOC而动态调整以改变功率分配。首先,通过分析储能SOC与虚拟惯性的关系,并考虑储能充放电极限问题,研究兼顾SOC、电压变化率以及电压幅值的自适应虚拟惯性控制策略,提高系统惯性。然后,建立控制系统的小信号模型,分析虚拟惯性系数对系统的影响。最后,基于Matlab/Simulink搭建直流配电网仿真模型,验证了所提控制策略能合理分配HESS功率,提高超级电容器利用率,改善直流电压与功率稳定性。

The DC power distribution network of electric power electronics has the problem of low inertia,which is not conducive to the stable operation of the system.Hybrid energy storage devices can provide virtual inertia to the power grid,but there is a power coordination problem between different types of energy storage,and the state of charge(SOC)of energy storage is a constraint on the adjustment of virtual inertia.To solve the above problems,a frequency division control strategy with an adaptive time constant is proposed.The time constant is dynamically adjusted according to the SOC of a hybrid energy storage system(HESS)to change the power distribution.First,by analyzing the relationship between energy storage SOC and virtual inertia,and considering the charging and discharging limit of energy storage,the adaptive virtual inertia control strategy that takes into account SOC,voltage change rate and amplitude is studied to improve system inertia.Then a small signal model of the control system is established,and the influence of virtual inertia coefficient on the system is analyzed.Finally,based on Matlab/Simulink,a simulation model of a DC distribution network is established to verify that the proposed control strategy can rationally distribute HESS power,improve the utilization rate of supercapacitors,and enhance the stability of DC voltage and power.