考虑SOC与电压信号的直流微电网变下垂截距虚拟惯性控制

Virtual Inertial Control of DC Microgrid with Variable Droop Intercept Considering SOC and Voltage Signals

为解决高渗透率直流微电网带来的低惯性问题,利用储能单元充放电提供的惯性支持能力,提出一种考虑SOC与电压信号的直流微电网变下垂截距虚拟惯性控制策略。首先,考虑荷电状态与电压波动约束,建立复合控制函数对下垂截距进行调节,使储能单元支撑功率均衡分配,又能跟随电压波动迅速动作,给系统提供惯性支持;其次,建立直流微电网小信号模型,给出变下垂截距定量约束,并论证了该约束内系统的稳定性;最后,利用MATLAB/Simulink仿真算例验证了该策略在储能单元充放电极限区域内的可行性,结果表明所提方法不仅能够增强系统惯性,还可实现储能单元的功率均衡。

To solve the low inertia problem caused by the high permeability DC microgrid,this research proposes a variable droop intercept virtual inertia control strategy for DC microgrid considering SOC and voltage signals,using the inertia support ability provided by charging and discharging of energy storage units.First of all,considering the constraints of charge state and voltage fluctuation,a composite control function is established to adjust the droop intercept,so that the energy storage unit can support the balanced distribution of power and act quickly with voltage fluctuation,providing inertial support to the system.Then,the small-signal model of the DC microgrid is established,the quantitative constraint of variable droop intercept is given,and the stability of the system within this constraint is demonstrated.Finally,the MATLAB/Simulink simulation example is used to verify the feasibility of this strategy in the charging and discharging limit region of the energy storage unit.The results show that the proposed method can not only enhance the system inertia but also realize the power balance of the energy storage unit.