An Inverter Parallel Control Strategy Research on Variable Virtual Impedance

In order to solve the imbalance distribution of reactive power in the power system caused by different line impedance in parallel muti-inverter system, This paper analyses the deficiency of traditional droop control and the causes of reactive current circulation. Double closed loop control based on inverter voltage and current, it studies the influence of different system parameters on the equivalent impedance of the inverter, according to the study it introduce virtual impedance, the real-time reactive power is distributed to a given reactive power through the inverter's control system, and then the inverter control system estimates the virtual impedance by deviating the reactive power from the given reactive power. Simulation results show that the method of adjust reactive power on line have certain effectiveness and feasibility. (paper)