基于下垂控制的环流抑制策略及仿真建模

Circulating Current Reduction Technology Based on Droop Control and Simulation

并联逆变器I的等效线路阻抗不仅会影响无功功率分配,还会产生环流。为此,提出一种基于虚拟阻抗自补偿的改进下垂控制。通过引入一个给定虚拟阻抗,并对其进行多次补偿,不断减小系统的阻抗差异。一方面提高无功功率分配精度;另一方面可以减小环流,同时加快系统的动态响应和避免电网电压压降过大。最后,通过MATLAB/Simulink仿真与搭建实物样机并进行相应实验,验证了理论分析的可行性。

The difference between the equivalent line impedance of the parallel inverters not only affects the reactive power distribution,but also generates circulating current.Conventional droop control has limitations on the suppression of circulating current,for which an improved droop control based on virtual impedance self-compensation is proposed.A setting virtual impedance is introduced to the system,and the impedance difference of the system is continuously reduced by making multiple compensations of the setting virtual impedance.On the one hand,it improves the reactive power distribution accuracy,on the other hand,it can reduce the circulating current.At the same time it can speed up the dynamic response of the system and avoid excessive voltage drop of the grid.The simulation results verify the correctness and effectiveness of the improved droop control.