光储混合直流微电网非线性分层控制策略

Nonlinear Hierarchical Control Strategy for Hybrid DC Microgrid

针对光储混合直流微电网中光伏出力或负荷突变容易导致直流母线电压波动问题,提出了一种基于非线性分层控制方法。该方法的上层控制通过对各功率单元协调控制以维持直流母线电压的稳定,并可为底层各功率单元的控制提供参考指令。底层则采用非线性控制策略分别对光伏阵列的出力、蓄电池以及超级电容器的充放电进行控制,进而保证直流母线电压能够在光伏出力波动或负荷突变时维持动态稳定。通过推导底层各控制单元以及整个系统的李雅普若夫函数对系统的稳定性进行了验证。最后,通过仿真对所提方法的有效性进行了验证,实验结果表明所提方法比传统的线性控制方法具有更好调节效果。

A nonlinear hierarchical control method was proposed to solve the problem of DC bus voltage fluctuation caused by sudden change of photovoltaic output or load in DC microgrid.The upper control maintains the stability of DC bus voltage by coordinating the control of each power unit,and provides reference instructions for the control of each power unit at the bottom.The bottom layer adopts nonlinear control strategy to control the output of photovoltaic array,the charge and discharge of battery and super-capacitor respectively,so as to ensure that the DC bus voltage can maintain dynamic stability in case of photovoltaic output fluctuation or load sudden change.The stability of the system was verified by deriving the Lyapunov function of each bottom control unit and the whole system.The effectiveness of the proposed method was verified by simulation.The experimental results show that the proposed method has better control effect than the traditional linear control method.