基于并联虚拟电阻的多逆变器控制策略

摘要

In micro-grid,power sharing and circulation current suppression are critical problems for the control of parallel inverters.Low precision of power sharing and circulation current are caused by different line impedances.For these issues,a new kind of control strategy for multi-inverters is proposed based on parallel virtual resistance.The voltage tracking system of inverter is designed and the inner loop current reference is modified by the current of virtual branch.Then,the value of inverter's equivalent connection impedance is changed.As a result,the precision of power sharing is improved and circulation current is also suppressed.With bode diagram of inverter's equivalent output impedance,the relevant control parameters of voltage tracking system are well designed.Simulation model is set up in Matlab/Simulink and simulation results show the validity of the proposed control strategy.%功率均分与环流抑制是微电网中逆变器并联控制的关键问题.针对线路阻抗差异造成的系统功率均分精度低下及系统环流等问题,提出一种基于并联虚拟电阻的多逆变器控制策略.通过对各逆变器的电压跟踪系统进行设计,利用虚拟支路电流对内环电流参考值进行强制修正,从而改变各逆变器的等效连接阻抗,实现系统功率均分精度的提高及环流抑制.最后,结合逆变器等效输出阻抗的伯德图,对电压跟踪系统中的相关控制参数进行了选择.在Matlab/Simulink中搭建了仿真模型,验证了新方法的有效性.