直流微电网中能量协调控制策略的研究

Research on Energy Coordination Control Strategy in DC Microgrid

为解决直流微电网中母线电压稳定和能量流动平衡的问题,提出了基于直流微电网能量平衡关系的切换控制策略,将直流微电网的母线电压平衡转化为能量平衡,并将直流微电网建模为具有5种模式的线性切换系统,针对每种模式设计了稳定母线电压的控制器;为实现模式之间的无缝平滑切换,在任意切换稳定的基础上,针对微电网的能量流动特点,给出相应的模式切换规则。通过理论分析可知,该切换控制策略能够很好地实现母线电压稳定和能量平衡,对单一模式以及模式之间的切换进行了仿真研究,结果表明:该控制策略能在功率不平衡时,将母线电压波动控制在额定电压的±5%以内并能快速恢复到期望电压。

Aiming of the bus voltage stability and energy flow balance in DC microgrids,a switching control strategy based on the energy balance relationship of DC microgrid is proposed.The bus voltage balance of DC microgrid is transformed into energy balance,and DC microgrid is modeled as a linear switching system with five modes.A controller is designed for each mode to stabilize the bus voltage.To achieve the seamless and smooth switching between modes,on the basis of maintaining the stability of any switching,the corresponding mode switching rules are given based on the energy flow characteristics of microgrid.Theoretical analysis shows that the switching control strategy can effectively achieve bus voltage stability and energy balance.The results of simulation on both individual modes and mode switching show that the control strategy can control bus voltage fluctuations within ±5% of the rated voltage and quickly return to the desired voltage in the case of power imbalance.