基于节点源荷电流差分的直流微电网储能变换器控制策略

Control Strategy of DC Microgrid Energy Storage Converter Based on Node Differential Current

直流微电网中分布式微源或负荷改变、线路短路,均会引起直流母线电压波动,储能单元的快速响应对于提高直流微电网稳定性至关重要,据此该文针对直流微电网储能变换器,提出一种基于节点源荷差分电流的控制策略。通过计算直流微电网源荷功率差额,确定储能交互功率,并计算储能调节电流,进而调节储能变换器占空比。相较有限集模型预测控制,省去了遍历储能变换器工作状态和寻优求解的过程,降低了在线计算量,且所提策略不受电感影响,提高了响应速度和精度,降低了直流微电网母线电压和负荷电流的波动。最后仿真和实验证实了所提策略的有效性。

In DC microgrid(DC MG),the variation of distributed generation power and load power,as well as the short circuit of transmission line,will cause the fluctuation of DC bus voltage.Therefore,the response speed of energy storage unit is very important to improve the stability of DC MG.In this paper,a control strategy based on node differential current(NDCC)for DC MG energy storage converter is proposed.By calculating the power difference between the source and load of the DC microgrid,the energy storage interaction power is determined,and the energy storage regulation current is calculated,so as to adjust the duty cycle of the energy storage converter.Compared with the finite set model predictive control,it eliminates the process of traversing the working state and optimization of the energy storage converter,reduces the amount of on-line calculation,and the proposed strategy is not affected by the inductance.Therefore,the response the speed and the accuracy are improved.The fluctuations of the bus voltage and the load current are also reduced.Finally,simulation and experiments verify the effectiveness of the proposed strategy.