基于模糊下垂补偿的直流微源并联改进控制

Improved Parallel Control of DC Micro-source Based on Fuzzy Droop Compensation

由于线路阻抗不可忽略,传统应用于直流微电网的DC/DC变换器的下垂控制会造成直流母线电压存在偏差,分布式单元输出电流/功率不均衡。因此,为了减小母线电压偏差并提高各单元输出电流/功率的均分程度,提出一种基于电压电流双补偿的改进下垂控制策略:利用模糊算法对电压偏差进行补偿,提升电压控制精度;同时通过相邻单元间的输出电流信息交互,精确分配各变换器的输出电流/功率。为了验证所提控制策略的可行性,分别搭建了基于双向有源桥(dual active bridge,DAB)结构的直流微电网模型,同时搭建了2台DAB并联的直流微网实物平台。仿真和实验结果证明了所提控制策略对于提升电压/电流控制精度的有效性和正确性。

Because the line impedance is not negligible,the droop control of DC/DC converter used in DC microgrid will cause the DC bus voltage deviation and the distributed unit output current/power imbalance.Therefore,in order to reduce the voltage deviation of the bus and improve the output current/power distribution degree of each unit,an improved droop control strategy based on double compensation of voltage and current is proposed.Fuzzy algorithm is used to compensate the voltage deviation and improve the voltage control precision.At the same time,the output current/power of each converter can be accurately allocated through the exchange of output current information between adjacent units.In order to verify the feasibility of the proposed control strategy,a DC microgrid model based on the dual active bridge(DAB) structure is built respectively,and two DAB parallel DC microgrid physical platforms are built at the same time.Simulation and experimental results show that the proposed control strategy is effective and correct for improving the voltage/current control accuracy.