基于双重下垂控制的多储能直流微电网能量管理策略

Energy Management Strategy for Microgrid of Multi-energy Storage Based on Dual Droop Control

直流微电网中的储能系统对于稳定母线电压、维持系统安全运行有着重要意义。传统下垂控制下,各储能单元线路阻抗的差异导致直流母线电压存在偏差且无法实现储能单元间功率的精确分配。为此,提出双重下垂控制,该算法采用两级下垂控制,改进后的一级下垂控制用于补偿线路阻抗造成的功率偏差,实现直流母线电压稳定;二级下垂控制实现同类型储能单元间的功率分配。在考虑母线电压波动幅度基础上,分析了储能单元变换器带下垂特性的功率电压曲线,研究了下垂系数的选取范围。建立该控制策略下的系统模型,通过根轨迹分析补偿因子、下垂系数、电压控制器以及电流控制器参数对系统稳定性的影响规律。最后,在MATLAB/Simulink上的仿真结果表明所提方法能实现同类储能单元的功率精确分配和稳定母线电压,且对系统单点故障具有较强鲁棒性。

The energy storage system is of great significance in stabilizing the bus voltage and the safe operation in DC microgrid.The difference of line impedance between energy storage units leads to the deviation of DC bus voltage and thus the power can not be distributed accurately between energy storage units.This paper proposes dual droop control,which adopts two-stage droop control.The improved first-stage droop control compensates the power deviation caused by line impedance and realizes the voltage stability.The second-stage droop control realizes the power distribution accurately.After the fluctuation amplitude of bus voltage is taken into account,this paper analyses the power voltage curve of con-verter with droop characteristics,and studies the selection range of droop coefficient.The system model is developed to investigate the effects of coupling relationship in the system parameters.Finally,the simulation results in the MATLAB/Simulink verify the effectiveness and robustness of the proposed method.